ARTIKEL ELEKTRONIKA | SKEMA RANGKAIAN ELEKTRO | APLIKASI ELEKTRONIKA: Juni 2011

UNIPOLAR STEPPER MOTOR DRIVER CIRCUIT

Rangkaian Unipolar Stepper Motor Driver, The stepping rate is shown being set by a 1 Megohm potentiometer (RT). Using the component values shown for R1, RT, R2 and C1, the calculated step rate range is between 0.72 steps per second (1.39 seconds) to 145 steps per second.

The LM555 (IC 1) astable oscillator produces CLOCK pulses that are fed to PIN 11 of the 74194 (IC 2) shift register.

Each time the output of the LM555 timer goes HIGH (positive) the HIGH state at the 74194's OUTPUT terminals, (PIN's 12, 13, 14, 15), is shifted either UP or DOWN by one place.

The direction of the output shifting is controlled by switch S1. When S1 is in the OFF position (centre) the HIGH output state will remain at its last position and the motor will be stopped.

Switch S1 controls the direction indirectly through transistors Q2 and Q3.

When the base of Q2 is LOW the output shifting of IC 2 will be pins 15 - 14 - 13 - 12 - 15; .etc.

When the base of Q3 is LOW the output shifting of IC 2 will be pins 12 - 13 - 14 - 15 - 12; .etc.

The direction of the output's shifting determines the direction of the motor's rotation.

The outputs of the 74194 are fed to four sets of paralleled segments of a ULN2803 Darlington driver (IC 3).

When an input of a ULN2803 segment is HIGH, its darlington transistor will turn ON and that OUTPUT will conduct current through one of the motors coils.

As the coils of the motor are turned ON in sequence the motor's armature rotates to follow these changes. Refer to following diagram.

RANGKAIAN SWITCHING POWER SUPPLY

Rangkaian Switching Power Supply Sederhana , LM2575 series of regulators are monolithic integrated circuits that provide all the active functions for a step-down (buck) switching regulator, capable of driving a 1A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3V, 5V, 12V, 15V, and an adjustable output version.

Requiring a minimum number of external components, these regulators are simple to use and include internal frequency compensation and a fixed-frequency oscillator.

The LM2575 series offers a high-efficiency replacement for popular three-terminal linear regulators. It substantially reduces the size of the heat sink, and in many cases no heat sink is required.

A standard series of inductors optimized for use with the LM2575 are available from several different manufacturers. This feature greatly simplifies the design of switch-mode power supplies.

Other features include a guaranteed ±4% tolerance on output voltage within specified input voltages and output load conditions, and ±10% on the oscillator frequency. External shutdown is included, featuring 50 µA (typical) standby current. The output switch includes cycle-by-cycle current limiting, as well as thermal shutdown for full protection under fault conditions.

RANGKAIAN PENGONTROL SPEED UNTUK BOR PCB

Rangkaian Pengontrol Kecepatan Untuk Bor PCB, The affection of this ambit is the ICLM3578 which is a actual able chip switching regulator that can be acclimated for applications like this. The LM3578 has abstracted inverting and non inverting acknowledgment inputs (pin1 and pin2), 1V centralized advertence voltage antecedent and a congenital in oscillator circuit. The IC can be configured to access up to 90% assignment cycle. In the circuit, capacitor C2 is the timing capacitor which determines the abundance of the centralized oscillator. The assignment aeon depends on the sum of resistors R1 and R2 and it can be assorted by adjusting the POT R2. The achievement PWM arresting will be accessible at pin 5 of the IC. The Q1 drives the motor M according to the PWM arresting accessible at pin5 and appropriately by capricious the assignment aeon of the PWM beachcomber by capricious POT R2, the acceleration of the motor can be adjusted. The diode D1 is a freewheeling diode which protects the MOSFET Q1 from transients produced by the motor. Capacitor C3 is aloof a clarify capacitor.

SIMPLE WATER LEVEL DETECTOR

Rangkaian Pendeteksi Level Air Sederhana or Simple Water Level Detector. This is so advantageous ambit diagram because this ambit helps us to ascertain water.When the baptize appear and blow the sensors it will accomplish a sound.Here I accept acclimated accepted transistor bc109. Actually you can adapt this circuit.. By application a broadcast you can about-face on or off your baptize motor I will acquaint you them in my abutting post.

RANGKAIAN GENERATOR TEGANGAN TINGGI

Rangkaian Generator Tegangan Tinggi, The achievement voltage of this ambit is in Kilo volts and it can actively abuse you or annihilate you. Try this ambit alone if you accept abundant acquaintance ambidextrous with aerial voltages. I accept no albatross on any hazards acquired by the circuit. Be actual careful. This is a apprehensive request.

The ambit accustomed actuality has three sections namely oscillator, switching date and a footfall up stage. The oscillator is body about a NE555 timer operating at 25 KHz. The achievement of the NE555 accompanying to the abject of the ability transistor TIP3055 which is the switching device. The ability transistor drives primary of the footfall up agent at 25 KHz and as a aftereffect a aerial voltage will be induced beyond its secondary.

FM-VHF AMPLIFIER BOOSTER TRANSMITTER CIRCUIT

Rangkaian FM-VHF Amplifier Booster Transmitter, The amplifier chip is an integrated circuit containing multiple transistor stages and all other parts conveniently within a single small package. Boosting your FM transmitter has never been easier and the output signal can also directly drive 2n4427 or 2n3886 transistors for 1W or 5W of RF output power.

Specifications
Output Power: 500mW
Input Frequency: 50MHz - 1300MHz
Voltage Supply: 9-12V

RADIO RECEIVER TDA7088T STEREOPHONIC

TDA7088T Stereophonic Radio Receiver, Stereophonic radio broadcast is performed in the ultra short waveband, from 88 MHz till 108 MHz. All radio transmitters operating in this range are stereophonic, but their signal is designed so that monophonic receivers can also read it, performing the compatibility. The readers that wish to get acquainted in more details with the stereophonic broadcast basics can refer to the “Radio Receivers” textbook, for the IV grade of the Electrotechnical Highschool.

Making an introduction to this part, a operating principle of the stereophonic radio receiver shall be considered, its block diagram shown on pic.4.18. Comparing this diagram with the one of the monophonic receiver given on pic.4.6, one may notice that they are identical, up to the block called "The Decoder". It means that, as already described, exiting the FM detector the LF signal is obtained, i.e. the information that was used to perform the frequency modulation in the transmitter. However, this is not an ordinary LF signal, but the one, called the "composed" (KS) or "multiplexed" (Mpx) signal. Besides the full-scale LF signal used by the monophonic receiver,

it also contains the so-called auxiliary signal which allows the separation of left (L) and right (R) channels in the stereophonic receiver. E.g. if a direct broadcast of some band music is performed, the left part of performers is being recorded with one microphone (the signal marked as L), whilst the right side is recorded with the other one (it’s a R signal). These two signals are being led in the FM transmitter in the stage called “the coder”. Exiting the coder we have the multiplexed signal Mpx which contains, in an indirect manner, both left (L) and right (R) signal. Frequency modulation of the transmitter is being performed with the Mpx signal. In the receiver, Mpx signal is obtained on the output of the FM Detector and is then led to the decoder. This stage plays a role complementary to the one of the coder in the transmitter, therefore two signals are exiting it, the L and D signal. They are being amplified over two identical audio amplifiers, then reproduced over two same loudspeakers. The listener can now hear the left half of the performers from the loudspeaker placed on its left, and the right half from the loudspeaker that is placed on its right. The performers that are situated in the middle of the orchestra are being equally reproduced from both loudspeakers, making an impression to the listener as if there’s a third loudspeaker, located in the middle, between the left and right one. Based on all this, the listener has a picture about the layout of the performers in space, which significantly improves the total musical impression.
Electronic circuit of a portable stereophonic radio receiver with headphones reproduction, made with TDA7088T is shown on pic.4.19. It is a receiver whose practical realization was described in the previous project, with decoder with TDA7040T and dual audio amplifier with TDA7050T blocks added, the latter was discussed in PE5.
* L3, L4 and L5 are HF chokes that allow for the headphones cable to be used as a reception antenna. This is accomplished by connecting one of the headphones’ contacts from the plug-in, over the 10 pF capacitor, to the point where, acc. to pic.4.14, the outside antenna is connected. The coils represent big resistance to the station signals, preventing them to “go to ground” over the 47 mF capacitor or over the TDA7050T output. Each coil has 3 quirks of the 0.2 mm CuL wire, threaded through ferrite pearls, as shown on detail in the right corner of the pic.4.19. If telescopic antenna is to be used, these coils should be omitted.

Via : http://www.mikroe.com/en/books/rrbook/chapter4/chapter4c.htm

AM RECEIVERS SUPERHETERODYNE

Superheterodyne AM Receivers, you can see the block diagram of a radio-broadcast superheterodyne receiver The input circuit (UK) refines the signal of the tuned station from all the voltages created in the antenna (A) by various radio transmitters and sources of disturbances. In our example, it's an AM signal that has the carrier frequency fs, and is modulated by a single tone, as seen in the rectangle above its label. This signal is being led into the stage called the mixer. Another voltage is also led into it, the voltage from the local oscillator that has the frequency of f0, and a constant amplitude. Under the effect of these two signals, the phenomenon called the outbreak takes place in the mixer, and an AM signal appears on its output, its frequency being fm=455kHz. This signal is called the inter-frequency (IF) signal, and its frequency fm the interfrequency. The IF signal has the same envelope as the station signal entering the mixer. That means, that the information from the transmitter to the mixer is carried by the signal frequency fs, and in the mixer it is being assumed by a new carrier, that has the frequency fm. When transferring to another station, the user changes the capacitance of the variable capacitor C by turning the knob, setting up the resonance frequency of the input circuit to be equal to that station's one. Another variable capacitor, Co, is located on the same shaft as C, so its capacitance changes simultaneously to that of C. This capacitor is located in the local oscillator and that is how it gets the new oscillating frequency, having such value that the difference of the oscillator and station frequencies is again equal to the inter-frequency value.
Here's one numerical example. The interfrequency is being adopted by the constructor of the device, and it is mostly fm=455 kHz. When the receiver is set to the station that has the frequency of fm=684 kHz, the frequency of the local oscillator shall be fO=1139 kHz, therefore making there difference be
1139 kHz-684 kHz=455 kHz=fm.
When tuning to a station that operates on the frequency of fS=1008 kHz, the listener will change the capacitances of the two capacitors until the resonant frequency of the input circuit becomes fS=1008 kHz, and the oscillator frequency fO=1463 kHz, therefore yielding
1463 kHz-1008 kHz=455 kHz=fm.
If the receiver has more wavebands (LW, MW, SW1, SW2…) it is being constructed to have the same inter-frequency value for all of them.
What do we gain with this change of the carrier frequency? So far we haven't mentioned one very important thing, that is that the input circuit can never be selective enough, to extrapolate only the signal of the tuned station, from all the signals that exist in the antenna. On the output of this circuit, besides the station signal, also signals of strong and local transmitters are obtained, especially the signals from the neighbouring channels (their frequency being very close to the one of the tuned station). All these signals are receiving new signal carriers in the mixing stage, with their frequencies deviating fm as much as their carrying frequencies differ from fS. E.g., if the input circuit is set on the station whose frequency is 1008 kHz, another two signals from the neighbouring channels can also emerge on its exit.

Their frequencies would be 999 kHz and 1017 kHz. The ordinary TRF receiver would in this case be totally incapable of suppressing those signals, which is not the case with the superheterodyne receiver. These 3 signals are entering the mixer, which gets the 1463 kHz voltage from the oscillator. The outbreak occurs, and 3 AM signals are exiting the stage, their frequencies being 455 kHz, 464 kHz and 446 kHz. All 3 signals go to the IF amplifier (MFP), which has several amplifying stages with oscillatory circuits set to 455 kHz, making it very selective, so it amplifies only the 455 kHz signal and suppresses the others enough not to disturb the reception.
the signal exiting the IF amplifier is led onto the detector (Det.), the LF voltage amplifier (NFP) and the output stage (IS), the circuits we spoke about in the previous projects.
The ARP signifies the circuit that turns back the DC component of the detected signal into the IF amplifier, to obtain the automatic amplification regulation.
Above every block on the picture you can see the signal shape exiting that block, as seen on the oscilloscope, in case the modulation in the transmitter is done by the single, sinusoidally-shaped tone. The upper part of the picture contains the average voltage amplifications for each block, for the mass-production devices. Total voltage amplification, which is the ratio of the voltage on the loudspeaker to the voltage in the antenna is A=750000. The amplification in decibels is therefore: A(dB)=20logA=117.5

Source: http://www.mikroe.com/en/books/rrbook/chapter4/chapter4a.htm

PIC18F2550 MICROCONTROLLER IN OSCILLOSCOPE BASED

Oscilloscope Based on PIC18F2550 Microcontroller

Programming The ATmega32

Burn the ATmega32 with AVR_oscilloscope.hex and baddest alien bright at the fuses section.

After that, you Must attenuate the JTAG interface from your ATmega32 microController. If you don't do that, the mega32 will appearance you the antecedent awning and back it go to the oscilloscope awning it will restart anon to the antecedent awning and it will break there for ever.

Calibrations

The alone 2 things you accept to calibrate is the LCD adverse trimmer P2 and the P1, to move the axle at the centermost of the LCD. To do that, administer alone the ability accumulation to the ambit and acclimatize the P2 up to the point you will see bright the appeared pixels on the screen. Then, acclimatize the P1 up to the point the axle is confused at the average of the LCD (at the accumbent band of the cross).

TV SCANLINE MEMORY BUFFER

This technique started on idea that VGA screen at 640x480 resolution is non-interlaced picture 60 Hz refresh rate and horizonal scan frequency of 2xNTSC horizonal scan frequency.

Using this method the whole picture is converted to TV screen. When all odd lines are handle in one picture, the even number scan lines are handled in the same way on next round. This method gives out nice interlaced NTSC TV picture from 640x480 VGA screen.

The converter handles 640x480 graphics nicely without any drivers and it is possible to have your VGA monitor showing the same picture at the same time. To ble able to show other VGA resolutions nicely a driver is need to set all VGA modes to 60 Hz refresh rate (the driver makes VGA card to add blank scanlines to the beginning and end of the picture to make it 480 line picture).

When conversion is needed for PAL TV, a driver is needed which sets all VGA modes to 50 Hz operation. The horizonal scan rate for PAL output is still made by halving the VGA horizonal scan rate, which gives a little bit too high horizonal scan rate for output PAL signal. This problem usually messes up the colors in many products (for proper PAL signal decoding the horizonal scan rate must be very accurately right in conjuction with the color subcarrier frequency).

The electronics itself become quite complicated. A typical circuit which connnect to VGA monitor output needs fast A/D converters for digitizing incoming video signal, small memory biffer for storing those signals and digital PAL/NTSC encoder. Because the basic conversion need quite much electronics, the manufacturers have typically added a flicker reducing circuits to their products. Flicker reduction circuit stores fre scanlines information and interpolate between those scanlines to get rid of some of the flickering. There are some special ICs in the marked which can do all this.

Application fields where this technique is used: Most inexpensive small external VGA to TV converters, VGA chipsets with built-in TV output

HANDPHONE NOKIA N900 MANUAL GUIDE

The Nokia N900 comes with the following specs and features:

* Quad-band EGSM nokia n900 manual specs850/900/1800/1900, WCDMA 900/1700/2100.
* Maemo 5 software and user interface with direct touch logic, 3D accelerated graphics, and multiwindow multitasking menu logic.
* 5 megapixel Carl Zeiss autofocus camera with dual LED flash (4:3 and 16:9 ratio); CMOS sensor, Carl Zeiss optics, Tessar lens 2.8/5.2; Focal length: 5.2; Focus range: 10 cm to infinity.
* 3.5? touch display with 800 x 480 pixels (WVGA) resolution, 3D Graphics acceleration with support for OpenGL ES 2.0.
* Total available application memory up to 1 GB (256 MB RAM, 768 MB virtual memory). Up to 32 GB internal storage. MicroSD memory card extension, hotswappable, up to 16 GB*
* Form:side-slider
* Dimensions:110.9 x 59.8 x 18 (19.55) mm
* Weight (with battery):181 g.
* Maemo Browser powered by Mozilla technology.
* Integrated A-GPS receiver.
* Bluetooth version 2.1
* Application: Maemo Browser, Phone, Conversations (SMS, Internet Messenger), Contacts, Camera, Photos, Media player, Email, Calendar, Ovi Maps, Clock, Notes, Calculator, PDF reader, File manager, RSS reader, Sketch, Games, Widgets, Application manager for downloads.

The following manual, user guide and operating instruction contain detail information on how to operate, manage, and set up your N900. The manual is divided into sections as follows:
Safety
Set up Your Device
Keys and Parts
First Start-up
Kickstand
Stylus
Use Accessories
Introduction
Basic Use
Personalize Your Device
Connect Your Device
Browse the Web
organize Your Contacts
Make Calls
Send Instant Messages Mail
Capture Images Record Video Clips
Share Your Image and Video Clips
Play Music and Video Clips
Find and Vies Location (GPS)
Synchronize and Transfer Content
Back up and Restore Data
Update Software and Install Apps
Manage Time
Use Utilities and Manage Data
Play Games
Modify Settings
Accessories
Battery
Index

FREQUENCY VOLTAGE CORVERTER LM311 CIRCUIT

LM331 Frequency Voltage Converter, The IC has a duke abounding of applications like analog to agenda conversion, continued appellation integration, voltage to abundance conversion, abundance to voltage conversion. Wide activating ambit and accomplished breadth makes the IC able-bodied acceptable for the applications mentioned above.

Here the LM331 is active as a abundance to voltage advocate which converts the ascribe abundance into a proportional voltage which is acutely beeline to the ascribe frequency. The abundance to voltage about-face is accomplished by appropriate the ascribe abundance application capacitor C3 and resistor R7 and agriculture the resultant beating alternation to the pin6 (threshold) of the IC. The abrogating activity bend of the resultant beating alternation at pin6 makes the congenital comparator ambit to activate the timer circuit. At any instant, the accepted abounding out of the accepted achievement pin (pin 6) will be proportional to the ascribe abundance and amount of the timing apparatus (R1 and C1). As a aftereffect a voltage (Vout) proportional to the ascribe abundance (Fin) will be accessible beyond the amount resistor R4.

POCKET RECEIVER WITH ZN414 AND LM386 ICS

IC ZN414 & LM386 Pocket AM Receiver , The author was taking notes in his lab while testing the receivers being described herein, and used them later to write this book. One remark about the receiver whose electrical diagram is given on Pic.3.35 was: “Works EXCELLENT”. The reader will probably ask himself: Isn’t this the aforementioned “The Best Receiver”? No, it isn’t, just remember: DE GUSTIBUS... If, however, you consider it to be “The One”, please send your vote on E-mail: tesla@drenik.net;
This device is very similar to the one being described in the previous project. The most important difference is that the LF signal exiting the ZN414 does not go to the transistor amplifier but to the power amplifier built around the LM386, which was used in some previous projects. Any other audio amplifier can be used instead, e.g. those on Pics. 3.15, 3.21 and 3.22.
With this receiver, special care should be taken regarding the voltage on pin No.1. As you did in previous project, put the potentiometer’s slider in mid-position, turn the receiver on and tune it to some station. Move the slider carefully, until you reach the optimum reception. Start changing the capacitance of the variable capacitor, covering its entire scope, to make sure that receiver works well in its entire operating range. If a problem occurs, re-position the slider again. When everything gets OK, turn the receiver off, disconnect the potentiometer, measure its resistance, and solder the resistor of such resistance on the board. The R2 resistance must be no less than 600 Ohms.

Via : http://www.mikroe.com/en/books/rrbook/chapter3/chapter3g.htm

HORN SIREN CIRCUIT INLINE CONNECTOR

Horn Siren circuit Inline Connector 2011 Chevrolet Impala Police Circuit Diagram, This accouterment permits chump affiliation of a about-face to baddest either horn or siren operation back the horn pad is pressed. A 0.35 mm² (22 gauge) wire is affiliated to an in-line adapter in the horn ambit of the apparatus console accouter beneath the apparatus panel. The end of this accouter addendum is in a 1.5m (5 ft) bend of wire coiled beneath the apparatus panel.

PHONECARD IN ELECTRONIC SAFETY LOCK

Electronic Safety Lock with Phonecard

The ATtiny26 apprehend the 16 aboriginal bytes of telecard and afresh abundance them to centralized eeprom of ATtiny26.

Back you admit any telecard to the aperture (telecard`s base) it will apprenticed the about-face SW1. The ATtiny it will acquire that new agenda admit in the aperture and go to apprehend it. Temporary will save the 16 aboriginal bytes of the agenda to the RAM and afterwards the ATtiny will chase in centralized eeprom to see if this telecard is registered to the system. if not, it will aces the Red LED. The ATtiny acquire 8 groups of 16 bytes each, arbitrary 8*16=128 bytes of eeprom memory.

The ATtiny of this ambit its alive with centralized RC oscillator at 1MHz, that is the absence ambience from the factory.

1. Annals a telecard to the system:

With any telecard in to the slot, columnist the SW2 to annals the agenda to the system. The ATtiny will chase the centralized eeprom for abandoned anamnesis accumulation (1 group=16 bytes with $0F values). If there is abandoned group, it will apprehend the 16 bytes from RAM and abundance them to the eeprom. Then, the ATtiny will reboot, displace the telecard, apprehend it afresh and analysis if the agenda is registered (by analyze the 16 bytes of telecard, with 1 accumulation at the time, with centralized eeprom) .

Now it will awful the Red LED and aces the blooming LED because we acquire annals this telecard to the system. At the aforementioned time it will arm the broadcast affiliated to PB6 pin via BC547.

The centralized eeprom of ATtiny26 is 128 bytes. So, we can annals up to 8 telecards (keys) to this memory.

(8 telecards)*(16 bytes for anniversary telecard)=128 bytes of centralized eeprom

2. Unregister an registered telecard from the system:

If for some acumen we don't appetite to use any of 8 registered telecard, we can unregister it from the system. We acquire to admit this agenda to the slot, the ATtiny acquire it (by aces the blooming led). If we columnist the SW3, the ATtiny will chase to centralized eeprom to acquisition were the 16 bytes are stored and annul them by address the amount $0F to this anamnesis group. Now the ATtiny will reboot, apprehend afresh the telecard, analyze the aboriginal 16 bytes of the agenda with the centralized eeprom and because we acquire unregister this agenda it will aces the red LED. This telecard is unregistered now. We can annals the agenda afresh if we appetite to, by chase the footfall 1.

3. Abolish absolute centralized eeprom of ATtiny26:

If we acquire annals 8 telecards to the arrangement and will try to annals 1 added (9th), back we columnist SW2 to annals the card, the ATtiny it will beam the Red and Blooming LEDs 4 times alternately. The alone way to annals some added telecard, is to unregister some one of 8 registered cards (step 2.) or to abolish absolute eeprom (writing the amount $0F to all locations). To abolish absolute eeprom (128 bytes 0-127) we acquire to columnist the SW3 button with NOT any agenda central to the slot, for 2 seconds, to ensure the ATtiny that we are not columnist the button SW3 by asccident . At this case the ATtiny it will beam the Red LED 4 times. Afterwards that, the centralized eeprom of ATtiny it will cleared.

ELECTRONIC CHURCH BELL CONTROLLER

Electronic Church Bell Controller circuit

This ambit is a abbey alarm controller. Basic basic is an ATmega32 microcontroller. At the ambit 2 24LC32 eeprom memories is actuality used, the 1st for centralized accepted melodies and the 2nd one is for user's compositions. This affection will be provided in the future.

As ascendancy I created a card who will be appeared on 4x20 LCD (Liquid Crystal Display). The card browsing can be done by 6 buttons at the face of the circuit's box (Menu, Up, Down, Enter, Start, Stop). The all firmware binds about 19Kbytes beam anamnesis and can be added by abacus new features-functions. This affairs has been writen in C in CVAVR compiler.

THE DIRECT SW RECEIVER FOR AM, AM-SSB & CW SINALS

Direct SW Receiver for AM, AM-SSB & CW Signals

You have been able to see one of them in the previous project (3.29-a), and here we’ll take a look at another one, which works so nice that we were sometimes having the impression it beats up much more sophisticated, modern supereterodyne receivers. Its electrical diagram is shown on Pic.3.29-b.
The coil L and capacitors C and C1 form a parallel oscillatory circuit whose role is to separate and amplify the signal of the tuned station, and to suppress all others. It doesn’t entirely succeed in that, however. The reason for this is small Q- factor of the oscillatory circuit, being such because of big energy losses in the circuitry. There are many kinds (reasons) of these losses, but we can imagine in first approximation that there’s a resistor RG in the circuit which represents these losses, its resistance being such that the oscillating current transforms itself into heat dissipation energy on it, its amount being the sum of all the (actual) losses in the circuit. We could, furthermore, solve the problem of these losses if connecting serially to RG a resistor RG’, whose resistance would be negative and equal to the value of RG by its absolute value. The overall resistance would then be zero, there would be no energy losses and the Q- factor would become infinite. The oscillatory circuit would, together with the components that create this negative resistance, become an oscillator capable of receiving SSB and CW signals.
We don’t really need an infinite Q- factor while receiving usual (conventional) AM RG by its absolute value. The resistances would not cancel each other completely, but the losses would be made very small, the Q- factor therefore becoming very big therefor increasing both the selectivity and sensitivity of the oscillatory circuit.
Transistors T1 and T2 constitute, together with resistor R3, a two-stage amplifier with strong positive feedback that has a negative dynamic input resistance. This negative resistance is connected between the leg No.3 on the coil and the ground, therefore superimposing itself with the resistance representing losses of the circuit. The quantity of this negative resistance depends on the amount of the DC current flowing through the transistors, which is being regulated by altering the DC voltage on the right end of the R3 resistor (by moving the slider of the P1 potentiometer).
The red LED D and the resistor R2 comprise a simple voltage stabilizer, obtaining 1.8 V of stabilized voltage on the P1. That means that the voltage on the right end of R3 shifts between 0 and 1.8 V while moving the slider of P1. The current flowing through the transistors thereat also changes, causing the voltage on the left end of R3 to vary between 0 and 0.6 V.
The signal of the station is being led from the leg No.3 of the coil into the collector-type detector made of T3, R3, R4 and C4. That is an AM signal detector that performs both signal detection and its amplification. Its name is the Audion. The LF signal is then, from the collector of T3, over the coupling capacitor C5, being led onto the sound volume potentiometer P2 and the audio amplifier. For the latter any of the earlier described devices can be used.
Tuning this receiver on the desired station requires both some knowledge and patience (that’s what finally “buried” this kind of receivers). Put the slider P1 in the upmost position. If strong whistling is heard that means the oscillating began. Move the slider carefully downwards until the oscillating stops. Then start slowly turning the rotor of the capacitor C until you come upon some station. If the whistling re-appears, move the slider of the potentiometer very little downwards, the whistling should stop and you should be able to hear the radio - station programme from the loudspeaker (loud and clear). For the next station tune yourself with C, then move the slider P1 upwards until the whistling appears, then put the slider back until it stops etc. All this may seem rather complex at first, but with a little practice and with two hands all will go quick and smooth.
The abovementioned method is for the signal reception of ordinary, broadcast stations. If you wish to receive the SSB and CW signals you should move the P1 slider upwards until the oscillating is achieved, so that articulate speech (SSB) or Morse code signs (CW) can be heard from the loudspeaker.

DELAY AND RELAY CIRCUIT DIAGRAM

Delay and Relay circuit, With the cap that is in the schematic you will get about a 6 sec adjournment till ability on. You can change the cap in this ambit to 470uF for about a 20 sec delay.

Delay and Relay Part list

2 x resistor

3 x transistor

1 x diode

1 x capacitor

1 x relay

Misc some wire, a board, etc.

RANGKAIAN CLASS B 45 WATT AMPLIFIER

Class B 45 Watt Amplifier

The main design targets for this amplifier were as follows:

Output power in the 40 - 70W range
Simple circuitry
Easy to locate, low cost components
Rugged performance
No setup

These goals were achieved by using a discrete-components op-amp driving a BJT complementary common-emitter output stage into Class B operation. In this way, for small output currents, the output transistors are turned off, and the op-amp provides all of the output current. At higher output currents, the power transistors conduct, and the contribution of the op-amp is limited to approximately 0.7/R11. The quiescent current of the op-amp biases the external transistors, and hence greatly reduces the range of crossover.

The idea sprang up from a letter published on Wireless World, December 1982, page 65 written by N. M. Allinson, then at the University of Keele, Staffordshire.
In this letter, op-amp ICs were intended as drivers but, as supply voltages up to +/- 35V are required for an amplifier of about 50W, the use of an op-amp made of discrete-components was then considered and the choice proved rewarding.

The discrete-components op-amp is based on a Douglas Self design. Nevertheless, his circuit featured quite obviously a Class A output stage. As for proper operation of this amplifier a Class B output stage op-amp is required, the original circuit was modified accordingly.

Using a mains transformer with a secondary winding rated at the common value of 25 + 25V (or 24 + 24V) and 100/120VA power, two amplifiers can be driven at 45W and 69W output power into 8 and 4 Ohms respectively, with very low distortion (less than 0.01% @ 1kHz and 20W into 8 Ohms).

300W SUBWOOFER AMPLIFIER CIRCUIT FROM BASIC POWER SUPPLY CIRCUIT

Basic Power Supply circuit for 300W Subwoofer Amplifier circuit, Use a 40-0-40 V transformer, rated at 300VA for accustomed use. For best connected power, a 50-0-50V (500VA or more) agent will be needed. This will accord a connected ability of about 450W, and aiguille ability of over 500W is accessible with a acceptable transformer. Remember my warnings about application the amp in this way, and the charge for the added achievement transistors, big heatsink and fan.

For 115V countries, the agglutinate should be 6A, and in all cases a apathetic draft agglutinate is appropriate because of the arrival accepted of the transformer. For annihilation aloft 300VA, a soft-start ambit is awful recommended (see Project 39).

The accumulation voltage can be accepted to be college than that quoted at no load, and beneath at abounding load. This is absolutely normal, and is due to the adjustment of the transformer. In some cases, it will not be accessible to access the rated ability if the agent is not abundantly rated.

Bridge rectifiers should be 35A types, and clarify capacitors charge be rated at a minimum of 63V (or 75V if you use 70V supplies). Wiring needs to be abundant gauge, and the DC charge be taken from the capacitors - not from the arch rectifier.

AUTOMOTIVE 12V to 20V AUDIO AMPLIFIER

Automotive 12V to +-20V Audio Amplifier Converter, The agent charge be advised to abate bark effect, it can be done application several cloistral allurement wire distinct affairs anchored calm but administering separately. The adjustment is done both by the agent about-face arrangement and capricious the assignment cycle. In my case i acclimated 5+5 , 10+10 turns accepting a footfall up arrangement of 2 (12->24) and downregulating the voltage to 20 via assignment aeon activating acclimatize performed by the PWM ambassador TL494.

The addition arrangement has to be a little college to affected diode losses, ambagious attrition and so on and ascribe voltage bead due to wire attrition from array to converter.

PARALLEL INTERFACE BOARD 8 BIT WITH USB

8 Bit Parallel Interface Board With USB, USB interface lath activity is acclimated to affix 8 (parallel) abstracts curve to the USB. Main basic of this activity is FT245BM. With a baby centralized FIFO (384 byte Tx, 128 bytes Rx) and 4 handshake curve which accomplish it acceptable for interfacing microcontroller designs to the USB. Wolfgang says that you can additionally use it as simple 8bit IO back the bitbang approach is enabled.

4 PHOTO DETECTOR PCB CIRCUIT DIAGRAM

The LM339 input detection voltage levels for the circuit as shown is set at 1/2 of the supply voltage. If a lower or higher detection level voltage is needed, the values of resistors R5 and R6 can be changed to suit.

NOTE When power is applied to the circuit, the outputs of the 556 timers will be HIGH for 1 release delay time period. (Until the timing capacitors have charged to 2/3rds of the supply voltage.)

There are RESET inputs for each LM556. These inputs do not have terminal block connections but do have pads with holes to solder wires to if needed. The RESET inputs could be used to force the outputs of the 556 timers LOW until the timing capacitors have fully charged after power is applied to the circuit but an external timer would be needed to accomplish this.

EMERGENCY LAMP IC 555 CIRCUIT DIAGRAM

Emergency Lamp 555 Sequence With these incredibly very simple and easy to make because each of the components simply accessible from the market place. Emergency Lamp Sequence With this particular 555 can flip to the light 5W-10W. The circuit is developed with the astable multivibrator together with the IC 555 that is certainly employed to mendrive transformer by way of Q1. For extra details is often viewed right in the series Emergency Lamp With 555 follows.

Functioning frequency range of 555 Emergency Lamp With this particular set of configurations R1, R2 and C2. T1 in sequence Emergency Lamp With 10V 500mA 555 is actually a transformer.

RANGKAIAN MICROCONTROLLER AT89S51 & ADC 0804

This moisture controller circuit is based on the MICROCONTROLLER AT89S51 & the ADC 0804. This project demonstrates how analog data is converted in to digital form, so it can be displayed on the LCD. It also covers the sub rooting of microcontroller interface with LCD. AT89S51 is an 8051 compatible microcontroller from the ATMEL family. ADC0804 is a single channel ADC, in this project it is configured in auto mode i.e. It converts the incoming analog signal into the digital form continuously without generating any interrupt.

This is done with the help of two probes which are used as sensor. This metallic probes are inserted into the soil of the field, when water supply to the is started the soil starts absorbing water, this results in the low resistance in between the two probes. As the soil becoming more and more wet stimulatingly the resistance between the two metallic probes goes on reducing this signal is provided to the ADC, it converts the analog signal into digital form, for the microcontroller use. Three push button keys are provided, through which the user can set the cutoff point of the moisture according to the crop requirement.

JAM DIGITAL MIKROKONTROLER AT89S51

The digital clock is 1 that displays time digitally, seven segment and switches are interfaced with 8051 microcontroller AT89C51. This circuit may be used in vehicles, houses, offices and many others. The moment the Vcc supply is supplied to this circuit, the clock begins from 00:00. Time is displayed on four 7 segments (in frequent anode configuration) by utilizing the notion of multiplexing. That is reached by utilizing timer interrupt (Timer0) of AT89C51 which is configured to refresh 7 segments. The segments are refreshed numerous periods in the 2nd for simultaneous show. The clock runs which has a delay of precisely a single 2nd. Timer1 is used to produce a time delay of a single second. The info pins (a-h) of the many segments are interconnected and get signal from port P2 in the microcontroller.

ELECTRONIC VOTING MACHINE AT89S8252 CIRCUIT

The AT89S8252 Electronic Voting Machine Circuit Diagram confidence of the voter in its flawless working is gradually building up and these machines are thus becoming quite popular throughout the country. Features of the electronic voting machine include avoidance of invalid votes and reduction of counting time and the consequent expenditure incurred on manpower deployment. By using the Microcontroller the voting machine can be built up easily.

RANGKAIAN INFRARED TRANSMITTER-RECEIVER 555

The Infrared transmitter and receiver circuit shown in the schematic diagram, frequency can be adjusted using R1 potentiometer (or trimmer pot). This oscillation makes sure if the signal can be distinguished from other source by the receiver.

The frequency of this filter is determined by L and C in the feedback path (from output to inverting input of the op-amp). D1 is inserted in the feedback path to enable rectifying very small signal, since the op-amp feedback mechanism will compensate the forward drop voltage of the diode. The last op-amp is employed as a comparator, with the threshold is adjustable via R3 potentiometer.

CIRCUIT OUTPUT DELAY AUDIO AMPLIFIER

Output Relay Delay Audio Amplifier Circuit

The Output Relay Delay Audio Amplifier Circuit which turns on the speaker output relay in the audio amplifier. The idea of the circuit is wait around 5 seconds ofter the power up until the spakers are switched to the amplfier output to avoid annoying “thump” sound from the speakers. Another feeature of this circuit is that is disconnects the speaker immdiatly when the power in the amplifier is cut off, so avoinding sometimes nasty sounds when you turn the equipments off.

Output Relay Delay Audio Amplifier Circuit Component list

C1 100 uF 40V electrolytic
C2 100 uF 40V electrolytic
D1 1N4007
D2 1N4148
Q1 BC547
R1 33 kohm 0.25W
R2 2.2 kohm 0.25W
RELAY 24V DC relay, coil resistance >300 ohm

Circuit operation :

Then power is applied to the power input of the circuit, the positive phase of AC voltage charges C1. Then C2 starts to charge slowly through R1. When the voltage in C2 rises, the emitter output voltage of Q1 rises tigether with voltage on C2. When the output voltage of Q2 is high enough (typically around 16..20V) the relay goes to on state and the relay witches connect the speakers to the amplifier output. It takes typically around 5 seconds after power up until the relay starts to condict.

TWO SPEED CONTACTOR FOR DC MOTOR NOTES

Two Speed Contactor DC Motor Notes

1. S1 closes K3 and thus causes M1 to operate. S2 activates K1 and K2, reconfiguring the batteries for series operation and thus causes M1 to operate at “fast” speed.

2. B1 and B2 should be chosen based on the current requirements of M1. Often, sealed lead-acid type batteries are available at local suppliers for surprisingly low prices. These batteries are ideal for things such as scooters, go-karts, etc.

3. The relays are standard automotive type relays, available cheaply from any auto parts store.

4. Your motor will depend on your requirements. 12V motors will normally run fine at 24V, and vice versa.

5. You will notice that in series mode, all three relays only pull power from B2. This is because the relays have 12V coils, and it is impossible to switch the batteries from series to parallel and keep power to the coils at the same time. This does, however, mean that B2 is discharged slighty before B1. This should normally not be an issue unless the batteries are being drained completely “dead”. Draining a battery dead is not good for it in any situation, and should be avoided. If you wish, you can use a small 12V battery to run the relays separately.

6. You can add two more speeds to this controller using the schematic below. It connects at points A and B shown above on the controller schematic.

THEORY RESET FOR MICROPROCESSOR

Theory Reset for Microprocesso, circuit detects long duration zero level signals (breaks) on a NRZ (non return to zero) serial data line. Normal serial characters spend a short time in the zero state, and do not cause a reset. Break signals are a exception to this, they hold the line low for an extended period.

The 10K/1N4148 parts keep the 2.2uF capacitor charged up. Low input signals go through the 10K resistor and slowly pull the charge on the 2.2uF capacitor down. High input signals quickly recharge the capacitor through the 1N4148 diode. A break signal lasts long enough to discharge the 2.2uF capacitor to the point where the following gate changes state.

The 1N4148 on the right allows a manual break switch to be used on the target CPU, pressing such a switch does not short out the preceding 74HC14 gate.

This circuit could be built with just 2 schmidt trigger non inverting buffers, the 74HC14 was chosen because it is a common part. The parallel inverters are also optional, single inverters work fine.

RS 232 RESET MICROPROCESSOR CIRCUIT

RS-232 Reset for Microprocesso, remote microprocessor to be reset by a controlling host by sending a break signal over an RS-232 or RS-422 serial line.
This is an ideal way to develop software on older EPROM-based systems. Modern EEPROM/NVRAM systems use JTAG interfaces for similar results.
A program loader for the Z80 CPU is available below. The circuit has also been used with the Motorola 68HC11 EVB and the BUFFALO monitor program. See my Linux Cross Assemblers page for more info.

COTACTOR DC TWO SPEED MOTOR CONTROLLER

Two Speed Contactor DC Motor Controller Circuit,
It is based around three 12V relays, two 12V batteries, two switches and of course a motor. Having no silicon to “fry”, it is quite reliable and robust. A contactor controller works by rearranging the two (or more) supply batteries between series and parallel. This gives the motor a slow speed (batteries in parallel, current adds) and a fast speed (batteries in series, voltage adds). This assures that both batteries are discharged equally. When the circuit is “at rest”, the batteries are connected in parallel, which allows easy recharging.

Notes

1. S1 closes K3 and thus causes M1 to operate. S2 activates K1 and K2, reconfiguring the batteries for series operation and thus causes M1 to operate at “fast” speed.

2. B1 and B2 should be chosen based on the current requirements of M1. Often, sealed lead-acid type batteries are available at local suppliers for surprisingly low prices. These batteries are ideal for things such as scooters, go-karts, etc.

3. The relays are standard automotive type relays, available cheaply from any auto parts store.

4. Your motor will depend on your requirements. 12V motors will normally run fine at 24V, and vice versa.

5. You will notice that in series mode, all three relays only pull power from B2. This is because the relays have 12V coils, and it is impossible to switch the batteries from series to parallel and keep power to the coils at the same time. This does, however, mean that B2 is discharged slighty before B1. This should normally not be an issue unless the batteries are being drained completely “dead”. Draining a battery dead is not good for it in any situation, and should be avoided. If you wish, you can use a small 12V battery to run the relays separately.

6. You can add two more speeds to this controller using the schematic below. It connects at points A and B shown above on the controller schematic.

MOTOR WIND TURBINE 12V DC SWITCHIING CIRCUIT

12V DC Motor Wind Turbine, thits a car starter motor wind turbine generator to provide energy conversion between the mechanical torque from the wind rotor turbines,and the connected 150V load. A gearless two or three bladed upwind wind turbine using a permanent magnet DC motor can be used to charge a battery for energy storage through a rectifier and a typical wind turbine configuration.
The switching transistors can be any high current type capable of switching 20 amps at 40 volts minimum such as the 2N3771 or the TIP35C, or use lower current transistors in parallel but use a heatsink. Darlington transistors such as the NPN 2N6284 or the NPN SGSD100. One suggested (but not tested) switching circuit could be: Possible Switching Circuit.

SWITCHING POWER ADAPTOR AC to DC 90 WATT

AC to DC 90 Watt Switching Power Adaptor

The MC33374 switching power adaptor combines the required converter functions with a unique programmable state controller. At various variable AC inputs, it is capable of serving up to 6 A current at 15V output voltage. This switching power adaptor is capable of providing an output power in excess of 150W with a fixed AC input of 100V, 115V, or 230V, and in excess of 90 W with a variable AC input that ranges from 85V to 265V.

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