Remote Control Tester | IR Remote Control Tester Circuit Diagram

Here’s a simple, low cost, and easy to construct infrared remote control tester. The tester is built around an easily available infrared receiver module (TSOP 1238).

Stereo Amplifier | Compact High-Performance 12V 20W Stereo Amplifier

Amplifiers which run from 12V DC generally don’t put out much power and they are usually not HiFi as well. But this little stereo amplifier ticks the power and low distortion boxes. With a 14.4V supply, it will deliver 20 watts per channel into 4-ohm loads at clipping while harmonic distortion at lower power levels is typically less than 0.03%.

This is an ideal project for anyone wanting a compact stereo amplifier that can run from a 12V battery. It could be just the ticket for buskers who want a small but gutsy amplifier which will run from an SLA battery or it could used anywhere that 12V DC is available – in cars, recreational vehicles, remote houses with 12V DC power or where ever.

Rotative Speed Controller Circuit for Borer, Driller

Car Boot Lamp Warning Circuit

On many cars, the boot light will not go out until the lid is properly closed. It is all too easy when unloading the car, to leave the lid ajar. If you are unlucky and the car remains unused for some time, the next time you try to start it, the lamp will have drained the battery and you will no doubt utter a few appropriate words. The circuit described here will give a warning of just such a situation. A mercury tilt switch is mounted in the boot so that as the lid is closed, its contacts close before the lid is completely shut. The supply for the circuit comes from the switched 12 V to the boot lamp and through the mercury switch. When the lid is properly closed, the boot lamp will go out and the supply to the circuit will go to zero. If however the lid is left ajar, the lamp will be on and the mercury switch will close the circuit.

AC voltage Stabilaizer | Automatic AC voltage Stabilaizer circuit

Safety Guard | 230v A.C Power Gard Circuit - Protects home appliances from voltage spikes

Protect your home appliances from voltage spikes with this simple time delay circuit. Whenever power to the appliances is switched on or resumes after mains failure, the oscillator starts oscillating and D5 blinks. This continues for three minutes. After that, Q14 output of IC CD4060 goes high to trigger the gate of the SCR through D4. At this moment, the voltage is available at the cathode of the SCR, which energizes the relay coil to activate the appliance and D6 glows. Switch SW1 is used for quick start without waiting for delay.

Mains Pulser Circuit

The pulsar is intended to switch the mains voltage on and off at intervals between just under a second and up to 10 minutes. This is useful, for instance, when a mains-operated equipment is to be tested for long periods, or for periodic switching of machinery. Transformer Tr1, the bridge rectifier , and regulator IC1 provide a stable 12V supply rail for IC2 and the relay. The timer is arranged so that the period-determining capacitor can be charged and discharged independently. Four time ranges can be selected by selecting capacitors with the aid of jumpers. Short-circuiting positions 1 and 2 gives the longest time, and short-circuiting none the shortest.

Door Closer Circuit | Garage Door Closer Circuit Just using Relays

I wanted to build a Garage Door Closing circuit without relying on integrated configurations (555 timer etc) to keep it simplistic. The circuit closes the garage door after two minutes with C3 and four minutes with the addition of C2. The timer relay is surprisingly accurate (+/- five seconds). Another feature is to ensure that the garage door actually did close, such as if it’s stopped mid-operation by the user.

Description:

S3 (magnetic N.C.) is located at the garage door and activates the circuit when the garage door opens.
RL1 is the reset timer. It’s maintained in the “on” position for two minutes by C3 while the trigger capacitor, C4, is charged. RL2 is the conduit, directing C4 to either RL3 or R1 to ground when off. Purpose of R1 is to prevent arching across contacts and a fast discharge. RL3’s contacts are connected to the Garage Door’s Momentary Switch and is sustained “on” for a half second by C5.

FBI siren Circuit with flashing Indicator light

This ultra-simple circuit will produce the familiar sound of sirens used by US police cars on emergency calls. A small lamp will also flash synchronously with the siren sound. The circuit is capable of powering loads greater than 1 A for one or more lamps or a powerful loudspeaker, the kit producing quite a bit of noise and light.

The circuit is built from two astable multivibrators, in this case the familiar 555 of which two are present in an NE556 case. Of course, you are free to use two 555s if that suits you better. Both timer ICs are configured to operate as astable multivibrators.

Universal Battery Charger | Low cost battery charger solution for charging of both NiCd and NiMh batteries

Here is the circuit diagram of a low cost universal charger for NiCD - NiMH batteries. This circuit is Ideal for car use. It has ability to transform a mains adapter in to a charger . This one can be used to charge cellular phone, toys, portables, video batteries, MP3 players, ... and has selectable charge current. An LED is located in circuit to indicate charging. Can be built on a general purpose PCB or a veroboard. I hope you really like it.

Picture of the circuit