Delayed activation 15V voltage source using LM317.

This circuit uses the LM317 voltage regulator. This voltage source also uses a bipolar PNP transistor and an electrolytic capacitor, to achieve a delayed activation of the voltage regulator

This simple humidity sensor circuit using a 555 timer, shows us the humidity level that a ground under test has. To achieve the goal, a couple of probes are used.

These probes are placed on the ground to be tested.

6-LED VU meter using one transistor

This simple 6-LED VU meter allows us to visualize the level of an audio signal. Due to its few components, it is a cheap circuit and easy to build. The components are very common and very easy to obtain.

This clock signal generator using 7400 IC, is an astable circuit which uses the TTL 7400 integrated circuit.

The 7400 IC has four 2 inputs NAND gates (NOT AND). We only use two gates of this integrated circuit.

Logic Probe using NOT Gates (Inverters)

This logic probe using NOT Gates is implemented with three NOT gates, one rectifier diode, two LEDs and two resistors.

Dimmer / AC motor speed controller

If you want to control the light level of a room or if you want to control the speed of a drill or a fan (devices that use AC motors), this is the circuit you are looking for

Water level controller circuit using CD4001

This water level controller circuit controls the level of water in a tank. Unlike mechanical controls using a floating buoy, this circuit uses two sensors, an upper sensor and a lower sensor,

Soldering Iron temperature controller circuit

You can buy a Soldering Iron temperature controller system with many features, but here we want to give a circuit for you to do it yourself.

Differential Temperature Controller.

This circuit measures the temperature difference between 2 sensors and activates a relay when they are different

This ON-OFF Switch circuit using a 555 timer is simple, useful and easy to implement.

This circuit has many applications on places where it is necessary to activate and deactivate (connect and disconnect) an electrical or electronic device.

20 Amp Variable Power Supply using LM317

This 20 Amp Variable Power Supply varies its output voltage from 1.5 to 15 volts and is based on the well-known variable voltage source configuration, where only the LM317 voltage regulator is used.

This Relaxation oscillator using an UJT transistor circuit serves to generate signals for power control devices such as thyristors, TRIACs