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,
Fuel Pump Cut-off Circuit
Fuel pump cut-off circuit for the car prevents the activation of the pump. Useful to increase the security level of a car which already has an alarm installed
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.
Motorcycle Alarm circuit with transistors and relay.
This alarm has, as main elements, 3 transistors, a relay and various sensors, including motion sensors.
Electronic Doorbell Circuit using a 555 timer and a CD4017 decade counter
Electronic Doorbell circuit that lets know that someone is at the door. Made with 555 timer and 4017 decade counter allowing to change the tone of each note
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.