Monday, August 22, 2011

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ON/OFF 24 HOURS TIMER CIRCUIT SCHEMATIC DIAGRAM

ON/OFF 24 HOURS TIMER CIRCUIT SCHEMATIC DIAGRAM

The Cmos 4060 is a 14-bit binary counter. However - only ten of those bits are connected to output pins. The 4060 also has two inverters - connected in series across pins 11, 10 & 9. Together with R3, R4, R5 and C3 - they form a simple oscillator.

While the oscillator is running - the 14-bit counter counts the number of oscillations - and the state of the count is reflected in the output pins. By adjusting R4 you can alter the frequency of the oscillator. So you can control the speed at which the count progresses. In other words - you can decide how long it will take for any given output pin to go high.

When that pin goes high - it switches the transistor - and the transistor in turn operates the relay. In single-shot mode - the output pin does a second job. It uses D1 to disable the oscillator - so the count stops with the output pin high.

If you want to use the timer in repeating mode - simply leave out D1. The count will carry on indefinitely. And the output pin will continue to switch the transistor on and off - at the same regular time intervals.

1 comment:

  1. Thanks a lot, i have made it, it's very stable and decent timer

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