Darkness detector circuit with audio output using 555

Darkness detector circuit with audio output using 555

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.

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Inverting Summing Amplifier using Op Amp

Inverting Summing Amplifier using Op Amp

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

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Clock signal generator using 7400 IC (PCB)

Clock signal generator using 7400 IC (PCB)

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)

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Lie Detector Circuit Using Two Transistors

Lie Detector Circuit Using Two Transistors

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.

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Surge Protection Circuit (Voltage Delay Circuit)

Surge Protection Circuit (Voltage Delay Circuit)

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. 

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