Home Projects Oscillators and timers Long Duration Timer



Long Duration Timer
author: Rajkumar Sharma


This project is a long duration timer


This timer project can be used to switch ON/OFF any device after a set time, this circuit can be used in lots of application like switched ON/OFF Radio, TV, Fan, Pump, kitchen timer, the circuit describe here its unique in its own.

Project has been designed around two CMOS IC CD4001 and CD4020.  Two gates of CD4001 make the oscillator and rest has been configured as flip-flop, BC547 transistor is to drive the Relay. Circuit is pretty simple, has jumpers to set the required time duration, Preset is to set the 1Hz oscillator. SW1 is to start the timer, SW2 Power on/off project. Relay output switch contacts can handle 230V AC @ 5Amps

Applications: TV, Audio Equipment’s, Radio, Fan, Pump, DC Motor, Electronic Projects ON/OFF  

Operation Supply: 12V DC Current
Consumption: 60mA
D3: Power Indicator
D2: Timer Operation Indicator
CN2: Supply Input
J1-J7: Time Set (Please see Schematic for Time Duration)
CN1: Relay Switch Connection Normally Open or Normally Closed
SW1: Timer Start
SW2: Timer Supply On/Off
PR1: 1Hz Frequency Set



 PCB Design


PCB top and bottom layers



120x90 spot



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