This darkness detector circuit beeps when the light drops below a certain level.

The main elements of this circuit are the 555 integrated circuit, working as an astable multivibrator and an LDR which is used as darkness sensor.

Inverting Summing Amplifier using Op Amp

The inverting summing amplifier using op amp outputs a voltage equal to the sum of the voltages it has in its inputs. The following explanation is based on an adder of three inputs, but applies to an adder of any number of inputs

What is an Op Amp? What is an Op Amp Open Loop?

Op Amp Open Loop Gain – Operational Amplifier Open Loop gain is given when there is no feedback path between the output and one of the two inputs

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

Clock signal generator using 7400 IC (PCB)

This clock signal generator is an astable circuit which uses the TTL 7400 integrated circuit. The 7400 IC has four 2 inputs NAND gates (NOT AND) but we only use two gates. Suggested Printed Circuit Board (PCB)

UJT Relaxation oscillator circuit

The UJT relaxation oscillator circuit is a non linear oscillator used to generate a nonsinusoidal repetitive output signals that can trigger power control devices such as SCRs and TRIACs.

12v to 24v converter

This 12VDC to 24VDC step up converter is very useful to power devices that run on 24 VDC when we have a 12VDC voltage source as it could be a car battery or alike.

Zener diode Voltage regulator Circuit Design / Diagram

This zener diode voltage regulator design / diagram is achieved with two elements: 1 zener diode, 1 resistor and some basic electronic formulas.

LM317 variable voltage regulator circuit diagram.

LM317 characteristics. How the voltage regulator circuit works, Regulator circuit operation improvement

How to make 12V 1A power supply using zener diode and transistors?

This 12V 1A power supply using zener diode and transistors allows us to obtain an output of approximately 11.4 volts with a very small percentage variation for a wide variety of loads.

Lie detector circuit using two transistors

This simple lie detector consists of two transistors and other additional components and can detect if a person does not tell truth (the person is lying), using two sensors placed directly on the skin.

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.