Electronic sound control circuit (applause)

This electronic sound control circuit works like a sound activated relay and can activate or deactivate a device connected to it, by two consecutive claps.

Twilight switch circuit with Op. Amp.and LDR

This Twilight switch circuit activates a light, a lamp, a motor, etc., at the time of sunset and performs the reverse process at dawn.

This is an ideal circuit for activating a security light that must be on all night.

This 12v battery charger circuit using a LM350 and LM301A op-amp.

This 12v battery charger circuit allows you to charge a 12-volt car battery using a LM350 voltage regulator and a LM301A operational amplifier.

12V Power Supply using Zener and 741 Op. Amp.

This 12V Power Supply has, as its main characteristic, a low output impedance. This is a very desirable feature in voltage sources and is achieved with a large open loop gain that the operational amplifier has.

Temperature alarm circuit with 741 operational amplifier

This temperature alarm circuit with operational amplifier activates a relay when the temperature of the place to be controlled exceeds a set level. Useful for an oven temperature control or a cooling system

This continuity tester using 741 operational amplifier, operates as a differential amplifier.

A good application for this circuit would be to test welds made on a printed circuit board. It could be also used to test continuity of wires, connections, etc.

1 Input – 4 Outputs Stereo Audio Splitter

This 1 Input – 4 Outputs Stereo Audio Splitter has a single input and 4 independent outputs, each amplified with an operational amplifier. Each op amp is configured as a voltage follower, to take advantage of its high input impedance and low output impedance, thus avoiding distortion in sound.

Differential Temperature Controller.

This circuit measures the temperature difference between 2 sensors and activates a relay when they are different. It is also possible to detect a temperature change, even when the two measured temperatures are normally different.

How to Make a Diode Tester Circuit using 741?

This diode tester circuit checks if the diode is in good condition and also determines its polarity. To accomplish our goal, we use an 741 operational amplifier (IC1) configured as an oscillator.

How to make a Light Sensitive Sound Generator Circuit?

An oscillator circuit may have many applications. The diagram below shows how to make it work as a light sensitive sound generator using a LDR and a 741 operactional amplifier.

How to make a car temperature alarm?
This car temperature alarm check the car engine temperature and warns us, by means of a sound signal, when the temperature exceeds a seted value

4-channel audio mixer using LM3900 IC

4 operational amplifiers, some resistors and capacitors to implement an audio mixer with a very simple design.