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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Twilight switch circuit with operational amplifier and LDR

Twilight switch circuit with operational amplifier and LDR

This Twilight switch circuit activates a light, a lamp, a motor, etc., at the time of sunset and performs the reverse process at dawn.

This is an ideal circuit for activating a security light that must be on all night.

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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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