Automatic Water pump controller using BJT

This is one of my favorite analog electronics projects because this is the lowest cost but efficient automatic water pump controller. Components require for this project are 3 BJT model BC547, 1 Buzzer, 1 Relay, 8 Resistors, 1 Diode, 1 Led, Wires for sensing water level.  So all the components cost not more than $1. I …

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