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,

Audio level indicator circuit using LM339

This audio level indicator is very interesting because it allows us to visualize the audio level intensity by connecting this circuit to the input of a loudspeaker.

Rain detector using two transistors

Rain detector using two transistors. Circuit that aims to alert the beginning of the rainfall. Its few components make it an interesting and easy project.

Surge Protection Circuit (Voltage Delay Circuit)

This Surge protection circuit is placed between the DC voltage source and the circuit that you want to power. This circuit delays the voltage given by the power source and allows the voltage to be applied to the circuit or device a few moments later.

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.

Dark detector circuit using LDR and relay

This circuit uses, as a main component, an LDR (photoresistor). An LDR changes its resistance value depending on the amount of light it received. The more light means less resistance, the less light means more resistance.

Microphone Mixer using operational amplifiers

This Microphone Mixer combines signals from 3 different sources (3 microphones) easily and economically.

Doorbell for Deaf People.

When a deaf person is alone in a house, it would be very difficult to realize that someone is knocking on the door without any visual warning signal.

Inverter for fluorescent lamps (12V to 120 / 220 VAC)

Simple circuit using the 555 timer, a transformer and a transistor Useful to use with a car battery.

12V Car battery Charger with SCR and Transistor

The 12V car battery charger with SCR circuit is useful when you want to charge a lead acid car battery that for some reason was discharged

5A Variable Power Supply with LM338 Voltage Regulator

The 5A Variable Power Supply uses the LM338 voltage regulator. The LM338 regulator works the same as the LM317 adjustable voltage regulator, known to all

Long Duration Timer with NOR Gates (CD4001)

Long duration timer or long delay time with NOR gates. This very simple circuit allows us to turn off the TV or radio in the event that we fall asleep