Control circuit for solar powered solenoid pump delivering water from well - has timer based circuit with control of pause period in pulsed cycle to meet current conditions of supply

摘要

The control circuit has a capacitor (C2) that is charged via a shunt resistor and when a set voltage is reached current flows through a Zener diode (ZD) and a transistor (T1) switches to allow a timer to operate. A further transistor (T2) responds and the coil of the solenoid pump receives pulses for operation. Located between the solar cell and the control circuit is a shunt, with the difference voltage generated by an operational amplifier with the pause period of the cycle fixed by an RC arrangement (C1, R1). ADVANTAGE - Simple circuit for control of pump operation.