Top Circuits Page 106

use microcontrollers to communicate in serial between the microcontroller (AVR-006 kit) with a computer. In this project we will use microcontroller AVR-006 from Circuits-Home. Before creating the program, the first job we have to do is understand about the....

learn to use microcontrollers to create traffic-light applications. In this project we will use microcontroller AVR-007 from Circuits-Home. Before creating the program, the first job we have to do is understand about the hardware specs...

a microcontroller to control a DC motor (permanent magnet DC, DC servo, stepper and DC). In this project we will use microcontroller AVR-008 from Circuits-Home. Because it can be used to control the 3 types of DC motors, the AVR-008 is often called the 3in1....

The circuit described here can create three different US-style` siren sounds: police, ambulance and fire engine. The desired sound can be selected using switch S1. The circuit can be used in toys (such as model vehicles), as part of an alarm system, and in....

A long time ago when telephones were so simple almost nothing could go amiss from an electrical point of view, Telecom operators installed surge protection on all telephone lines exposed to storm risks. Paradoxically, now that we are hooking up delicate and....

The video amplifier in the diagram is a well-known design. Simple, yet very useful, were it not for the ease with which the transistors can be damaged if the potentiometers (black level and signal amplitude) are in their extreme position. Fortunately, this....

Even if a large number of album titles once available on vinyl are now, little by little, being proposed as CDs, not all are available and far from it. You may have treasures in your collection that you would like to burn on CDs. First, preserving a CD is....

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This project involves constructing an energy efficient broad spectrum LED lamp system. The lamp is useful for indoor reflective room lighting. It has a broad color spectrum that more closely approximates the light of the sun when compared to fluorescent....

A basic mixer suitable for mixing microphones or even effects outputs. The overall gain from input to output is one if the pot related towards the input is full up. You can make this a net gain of ten (or any other reasonable gain) by reducing the input....

Many households are still graced by tube-type television sets. If you want to connect one of these large tellies to your stereo system to improve the sound quality, this is usually not a problem because there are plenty of SCART to Cinch adapters available....

Normally home appliances are controlled by means of switches, sensors, etc. However, physical contact with switches may be dangerous if there is any shorting. The circuit described here requires no physical contact for operating the appliance. You just need....

The preamplifier is intended for use with dynamic (moving coil MC) microphones with an impedance up to 200 © and balanced terminals. It is a fairly simple design, which may also be considered as a single stage instrument amplifier based on a Type NE5534 op....

Here`s a project that could be useful this summer on the beach, to stop anyone touching your things left on your beach towel while you`ve gone swimming; you might equally well use it at the office or workshop when you go back to work. In a very small space,....

It is intended for use as a dual audio power amplifier in battery-powered sound players. Specifications of TDA2822M are low quiescent current, low crossover distortion, supply voltage down to 1. 8 volts and minimum output power of around 450 mW/channel with....

LM3900 [ PDF ] OP consist of four independent and internally compensated amplifiers in DIL14 package that are designed for wide single power supply voltage. ..

The Ambient Power Module (APM) is a simple electronic circuit which, when connected to antenna and earth ground, will deliver low voltage up to several milliwatts. Generally a long wire antenna about 100` long and elevated in a horizontalposition about 30`....

The LTC ®6990 is a precision silicon oscillator with a programmable frequency range of 488Hz to 2MHz. It can be used as a fixed-frequency or voltage-controlled oscillator (VCO). The LTC6990 is part of the TimerBlox ® family of versatile silicon timing....

Police Siren circuit diagram. This circuit produces a sound similar to the police siren. It makes use of two 555 timer ICs used as...

Rain Alarm. This circuit gives out an alarm when its sensor is wetted by water. A 555 astable multivibrator is used...

10W Audio Amplifier with Bass-boost. High Quality, very simple design. No preamplifier required. Circuit diagram: Parts: P1 22K Log.Potentiometer (Dual-gang for...

18W Audio Amplifier. High Quality very simple unit -- No need for a preamplifier Circuit diagram: Amplifier parts: P1 = 22K Log.Potentiometer...

300W Subwoofer Power Amplifier. High power amps are not too common as projects, since they are by their nature normally difficult to build, and are expensive.  A small error during assembly...

5 band graphic equalizer using a single IC/chip. The BA3812L is a five-point graphic equalizer that has all the required functions integrated. ","0",..

To order boards, click to go to the ESP Purchase form. Verify the price and postage, then open the order form, fill it in and print it from your browser. Boards are sold only as a stereo pair, and are supplied with component overlay, circuit diagram, bill of....

R1_47K 1/4W Resistor R2_4K7 1/4W Resistor R3_22K 1/4W Resistor R4_1K 1/4W Resistor R5, R12, R13_330R 1/4W Resistors R6_1K5 1/4W Resistor R7_15K 1/4W Resistor R8_33K 1/4W Resistor R9_150K 1/4W Resistor R10_500R 1/2W Trimmer Cermet R11_39R 1/4W Resistor R14,....

60W Bass Amplifier. Low-cut and Bass controls Output power: 40W on 8 Ohm and 60W on 4 Ohm loads Amplifier circuit diagram: Amplifier...

Amp with Tone Controls & Soft Switching. Notes: The soft switching is enabled by a BD131 transistor wired as a switch in emitter follower configuration. The collector is wired to a permanent...

AUDIO AMP + 3KHz FILTER. This circuit is the audio amp section for a complete optical transmitter. The increased circuit and filters the voice audio signals from an electret microphone..

Audio Graphic Equaliser. Audio graphic equalizers are very common as commercial products (for Hi-fi, car audio and stage use) but circuits for them are very rarely published. I didn`t...

This is a 3 stage discrete amplifier with gain control. Alternative transistors such as BC109C, BC548, BC549, BC549C may be used with little change in performance. The first stage built around Q1 operates in common base configuration. This is unusuable in....

The project described in this article is a constant Q, fully expandable graphic equaliser. Where most conventional  graphic EQ circuits have a Q that is dependent on the setting of the pot, this one maintains the same Q at all settings. This is achieved by....

R1_2K2 1/4W Resistor R2_27K 1/4W Resistor R3, R4_2K2 1/2W Trimmers Cermet or Carbon (or 2K) R5_100R 1/4W Resistor R6_1K 1/4W Resistor R7, R8_330R 1/4W Resistors C1_22 µF 25V Electrolytic Capacitor C2_47pF 63V Polystyrene or Ceramic Capacitor C3, C4_100 µF....

The new version has PCBs available, and is recommended for the best sound quality. If you need tone controls, you should see Project 97 which has excellent sound quality, and includes tone controls Much has been made of preamps, but provided a few simple....

Simple Surround Sound Decoder. Introduction This surround-sound decoder is based on the Hafler principle, first discovered by David Hafler sometime in the early 1970s. The original idea...

Tone Control. Parts: Part Total Qty. Substitutions C1, C3, C5, C7, C15, C16 6 2.2uf Electrolytic Capacitor C2, C6 2 0.05uF Ceramic...

ULTRA PURE 125KHz SINE WAVE SIGNAL SOURCE . For some RFID systems, which is at 125KHz, a very low distortion signal source is required. The circuit on this page results in a 10-volt peak-peak signal into...

Ultrasonic Switch. C ircuit of a new type of remote control switch is described here. This circuit functions with inaudible...

The basis for this amplifier is published as Project 03, and makes no claim to be state of the art  in fact the base design is now over 20 years old. It is a simple amp to build, uses commonly available parts and is stable and reliable. The design featured....

Wiper Speed Control. A continuously working wiper in a car may prove to be a nuisance, especially when it is not raining heavily. By using the circuit described here one can vary sweeping rate of the wiper from once a second to once in ten seconds..

Wireless IR headphone transmitter. Audio input from PL1 frequency modulates the VCO section of a 4046 PLL chip. The VCO output drives Q1, a switching transistor. Q1 drives two IR LEDs. The...

Automatic Fan Control circuit. This circuit is ON / OFF 12V DC fan or die CPU fan factory IF temperature above normal again temperature.You Can Feed the temperature of VR1. This circuit uses...

Motorcycle Alarm Number 4. This is a simple - easy to build - transistor based motorcycle alarm. It`s designed to work at 12-volts. But - if you change the relay for one...

Assortment of Siren Circuits. This month I am making 3 different types of siren circuits based on the 555 timer.  The first circuit simulates the siren of a British police car. It uses two...

Constant Temperature Circuit. (C) G. Forrest Cook 1997 Introduction This circuit is a generic low power temperature controller that can be used for stabilizing temperature...

Doorbell for the Deaf. Circuit : Andy Collinson Email: [email protected] This circuit provides a delayed visual indication when a door bell switch is...

In the transmitter schematic, no ballast resistor is shown because most small LASER power supplies already have one built in. Yours may differ, and a resistor may be needed. ..

Latching Continuity Tester. Source: Eldon L. Knight, Tony van Roon A continuity tester is a must on every service bench for testing cables, pcboards, switches, motors, plugs, jacks,...

Lightning Activated Camera Shutter Trigger. This picture was taken using the circuit. This circuit is used to trigger a camera`s electronic shutter circuit when a flash of...

Single-chip digital voltmeter. This 4 1/2-digit DVM circuit is built around a Maxim ICL7129ACPL A/D converter and LCD driver. An ICL8069 CCZR 1.2-V band-gap reference diode is used for a...

Siren Circuit. This circuit is to generate sound siren when S1 is pressed and increate sound frequency because charged C1, S1 is released when the frequency decreated...

One-IC two-tones Siren. Double-tone Police sound. Single-tone old ambulance sound. Circuit diagram: Parts: R1,R3 470K 1/4W Resistors R2 680K 1/4W...

3-state sound generator with LM556 . LM556 is a dual timer that can be operated as two LM555. The two timers operate independently of each other sharing only VCC and ground.You can define timing...

Square wave generator with CD4070. with this circuit it can generate square wave up to 2 MHz In this example I use CD4070 CMOS. VDD :...

Electronic Combination Lock. This circuit is very basic to build. To open a the lock which is connected to the K1 Load you must press each momentary switch in the correct sequence. The...

Digital Step-Km Counter. Max. range: 9,950 meters with two digits. Slip it in pants` pocket for walking and jogging. Circuit diagram: Parts: R1,R3 22K 1/4W...

Audio Light Modulator. Audio light modulations add to the enjoyment of music during functions organised at home or outdoors. Presented here is one such simple circuit in which...

Christmas Star. This circuit can be used to construct an attractive Christmas Star. When we switch on this circuit, the brightness of lamp L1 gradually increases. When it...

Dark Detector with LM555 . This is a dark detector circuit. This circuit will generate sound if no light source and silence when light falling on CdS. CdS : Cadmium sulphide or cadmium...

IR illuminator for night-vision tv cameras and scopes. This source uses LEDs and an astable oscillator to control the switch, duty-cycle, and effective IR illumination output..

Light flashing circuit. This circuit is the small lamp flashing signal on every 1 second flash rate control by adjusting the lamp voltage R1.The rate is to generate...

Light Switch. This is a light switch or light activated relay circuit.The relay if LDR uncoverd and relays, if LDR VR1 covered. Adjust sensitive.LED for...

Optical toggle switch using a single Chip. Using dual flip-flop IC CD4027 employ a 555 based monostable circuit to supply input clock pulses. The circuit described here obviates this requirement. One...

Simple variable frequency oscillator. This is a very simple circuit utilising a 555 timer IC to generate square wave of frequency that can be adjusted by a potentiometer. With values given...

Control electrical appliances using PC. Here is a circuit for using the printer port of a PC, for control application using software and some interface hardware. The interface circuit along with the...

12V to 3V convertor. This is an simple and cheap circuit to convert voltage from 12V to 3V.In fact this is a basic regulator circuit. The output voltage...

Power pulse circuit by LM350 and NE555 . This circuit can use to drive lamp,power LED,DC motor etc. Adjust R5 for output amplitude.Adjust R1 for output power .The LM350 is adjustable 3-terminal...

SCC3 12 Volt 20 Amp Solar Charge Controller. A kit with the circuit board and parts for this circuit is available from CirKits. SCC3 - 12 Volt 20 Amp Solar Charge Controller (C) G. Forrest Cook June...

MINIATURE ISOLATED AC/DC POWER SUPPLY. This circuit uses a novel approach to produce a fully isolated and regulated 5 volts @30ma from the 120vac power line. It uses two tiny SCRs that alternately...

RS-232 Serial Interface Status Indicator Circuit. I designed this circuit many years ago and have used it several times since.  It uses a single logic IC to indicate the TXD and RXD...

There are several RS232 transceiver circuit used for commond communicated between microcontroller and other devices such as PCs or devices rs232. Here is a collection of RS232 transceiver circuits that use well-known for today. The circuit using MAX232,....

Self switching Power Supply. One of the main features of the regulated power supply circuit being presented is that though fixed-voltage regulator LM7805 is used in the circuit, its...

Variable AC Power Supply Circuit. In electronics, it is often handy to have a fully isolated variable AC power supply. With such a device you can safely test various AC powered circuits and...

1-Transistor FM Transmitter. R1 27k R2 56k R3 12k R4 100 C1 1u C2, C3 470p C4 6 to 10p C5 1-30p trimmer L1 etched on PCB or a...

3-3.5 Watt FM Transmitter. This is the schematic for an FM transmitter with 3 to 3.5 W output power that can be used between 90 and 110 MHz. Although the stability isn`t so bad, a...

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40 meter Direct Conversion Receiver. Using the circuit of 40-metre band direct-conversion receiver descr- ibed here, one can listen to amateur radio QSO signals in CW as well as in SSB mode in...

4W FM Transmitter. TECHNICAL CHARACTERISTICS: Stabilised tendency of catering: Vcc=12~16V Frequency of emission: 88~108MHz Consumption: 100~400mA Materially: The...

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AM Transmitter. It is illegal to operate a radio transmitter without a license in most countries. This ircuit is deliberately limited in power output but...

FM Beacon Broadcast Transmitter (88-108 MHz). This circuit will transmit a continuous audio tone on the FM broadcast band (88-108 MHz) which could used for remote control or security purposes. Circuit...

FM Telephone Bug. Here is a simple transmitter that when connected to a phone line, will transmit anything on that line (execpt the dial tone) to any FM radio. The frequency...

I have had a few inquiries about a low power FM transmitter, and this article should satisfy those who might want to build one. It is designed to use an input from another sound source (such as a guitar or microphone), and transmits on the commercial FM band....

Remote control using VHF modules. A few designs for remote control switches, using VG40T and VG40R remote control pair, are shown here. The miniature transmitter module shown in Fig. 1, which...

Sensitive FM Transmitter. Additional Notes The default for the capacitors type is ceramic, preferably the npo 1% type or equivalent. But basically nothing critical here. Use any...

Small Radio Transmitter. This article contains information about building a small radio transmitter, which has a PCB 1.75 x 2.5 (45mm x 68 mm) and has a range of about 30 yards or...

Transmitter FM 45W with valve. TECHNICAL CHARACTERISTICS: Tendency of catering: 220V AC Frequency of emission at FM: 88~108MHz Force of expense: max 45W (without the...

Wireless FM Transmitter. The photo shows a wireless FM transmitter, pocket radio and yellow disk for size comparisons. Speak into the transmitter and others hear you on any FM...

Wireless Telephone Bug. Here`s a neat little project that will allow you to monitor your phone line as soon as your phone is off hook. You can use a regular FM broadcast band radio...

Infrared Remote Control for operates on 115 volts AC. This circuit will allow you to turn on any piece of equipment that operates on 115 volts ac. The receiver circuit is based on the Radio Shack infrared...

An Infra Red wired Repeater circuit to control appliances from a remote location. Parts List: R1: 1k Resistor (1) R2: 3.3k Resistor (1) R3: 10k...

This Mark3 version of the Infra Red extender is a special version designed to control appliances that use high frequency modulated IR remote...

The latest addition to my collection of Infra Red (IR) Repeater circuits. The Mark 5 is a much improved version of the Mark 1 circuit and has increased range...

This is an improved IR remote control extender circuit. It has high noise immunity, is resistant to ambient and reflected light and has an increased range from...

Here is a teleremote circuit which enables switching on` and off` of appliances through telephone lines. It can be used to switch appliances from any distance, overcoming the limited range of infrared and radio remote controls. The circuit described here can....

Color sensor. Colour sensor is an interesting project for hobbyists. The cir- cuit can sense eight colours, i.e. blue, green and red (primary colours); magenta, yellow...

Dew sensor. Dew (condensed moisture) ad- versely affects the normal per- formance of sensitive electronic devices. A low-cost circuit described here can be used to...

Audio Visual Ringer. Many a times one needs an extra telephone ringer in an ad-joining room to know if there is an incoming call. For example, if the telephone is installed in...

Multipurpose Circuit for telephone. This add-on device for telephones can be connected in parallel to the telephone instrument. The circuit provides audio-visual indication of on-hook,...

Off line Telephone tester. Here is a circuit of an off-line telephone tester which does not require any telephone line for testing a telephone instrument. The circuit is so simple that...