# Category Archives: Circuit Diagrams

Useful circuit diagram for developer and easy applicable

# Motor Turn Stall Detector

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In single phase AC induction motors, often used in fridges and washing machines, a start winding is used during the starting phase. When the motor has reached a certain speed, this winding is turned off again. The start winding is slightly out of phase to the run winding. The motor… Read more »

# Infra-red Light Barrier Using 555

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This is a short-range light barrier for use as an intruder alarm in doorposts, etc. The 555 in the transmitter (Figure 1) oscillates at about 4.5 kHz, supplying pulses with a duty cycle of about 13% to keep power consumption within reason. Just about any infra-red LED (also called IRED)… Read more »

# Light Gate With Counter Using 555 And 4033

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The circuit described here counts the number of times that an infrared beam is interrupted. It could be used to count the number of people entering a room, for instance, or how often a ball or another object passes through an opening (handy for playing shuffleboard). The heart of the… Read more »

# 555 Timer Clap Switch

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This 555 timer clap switch circuit electronic project is designed using some common electronic parts. This 555 timer clap switch circuit electronic project operates from a distance of up to 10 meters from the microphone . Signal from microphone is amplified by transistors T1, T2 and T3. Diode D1 detects… Read more »

# 555 Touch Switch Circuit

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This circuit uses a 555 timer as the bases of the touch switch. You can learn more about 555 timers in the Learning section on my site. When the plate is touched the 555 timer is triggered and the output on pin 3 goes high turning on the LED and… Read more »

# 555 Timer Circuit With Variable On/Off Times

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This circuit enables the on/off times of a 555 timer to be independently varied over a wide range. This is not possible with a conventional 555 circuit with the RC network being charged from the positive supply rail and discharged via pin 7. Instead, the capacitor at pins 2 &… Read more »

# 555 DC/DC Converter

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It is all too often necessary to augment the power supply of an existing electronic circuit because exactly the voltage that you need is missing. The circuit presented here may provide a solution in a number of cases, since it can be used to convert a single-ended supply voltage into… Read more »

# 555 Police siren

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The Police Siren circuit uses two 555’s to produce an up-down wailing sound. The first 555 is wired as a low-frequency oscillator to control the VOLTAGE CONTROL pin 5 of the second 555. The voltage shift on pin 5 causes the frequency of the second oscillator to rise and fall.

# Hacks and Mods: VFD Talking Alarm Clock

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Are you having a hard time waking your hubby from sleeping? And when you leave the house for work, are you in doubt that he has not gotten out of bed? One thing that will stop your worries is to use this clock that does not just tell time but… Read more »

# Simple Darkness Activated Alarm

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Most darkness activated alarms employ opamps and some logic ICs. Here, a less expensive approach is shown based on the eternal 555, this time in monostable multivibrator mode. Components R2 and C1 represent a one-second network. When the LDR (light dependent resistor) is in the dark, its resistance is high,… Read more »