Settable On Off Long Duration Timer Circuit

Settable On Off Long Duration Timer Circuit is useful in turning air conditioner ON and OFF as per the requirement to reduce the power consumption without affecting the cooling considerably. Settable On/Off Long Duration Timer gives you adjustable ON & OFF timings from minutes to hours e.g. 4 minutes ON, 15 minutes OFF or 70 minutes ON, 10 minutes OFF. Other applications of this circuit can be household water pump ON/OFF, compressor ON/OFF in any compressed air system, blower ON/OFF in explosive gas environment.

About the circuit :
The circuit is built around two CMOS 4060 IC’s both working as independently settable oscillator cum counter /divider. Pin 9 & 10 have R, C components which decides the frequency of oscillator. This oscillator frequency is fed to chain of binary counters (14) through a resistance (R1, R6). Pin 7 is the output of fourth counter. LEDs D5, D6 indicates the clock pulses. Relay driver T3 is driven by pin 3 (last counter output) of  IC2.When pin 3 of IC2 goes high, IC2 output is latched by pulling down pin11 through T2 and LED D6 becomes steady. ON time starts here. Hi state at pin 3 drives the relay ON. At the same instance IC1 is resets through C2, R5 & oscillation and counting of IC1 starts. LED D5 starts pulsating. IC1 timing progresses. When pin 3 (of IC1) goes high IC2 gets reset pulse through C4, R10. Oscillator and counter of IC2 start again. LED D6 starts pulsating. Pin 3 of IC2 goes low on reset. Relay is switched OFF. ON time (IC1 timing) ends.IC2 oscillations start and the timing progresses through the chain of counters. The last output of counters that is pin 3 output goes high after the set (P2) timing i.e. OFF time. Load can be connected to NO and P ( Pole) of the relay output. The Relay can switch current up to 5 Amps. Settable On/Off Long Duration Timer can be set ON time & OFF time separately with relay O/P.