this feature makes it perfect to make simple long duration timers.
The circuit below is able to drive upto 13A load. For driving higher load than this it can be replaced with higher output mosfet like BUZ11 that is able to drive upto 30A load. Pressing the push switch S1 charge the 220uF capacitor and switch ON the 2N3904 transistor. When 2N3904 become switch ON it will connects the Gate of the mosfet to the positive rail, this makes the mosfet switch ON and supply power to the load until the 220uF capacitor will discharge.
Usually long duration timers are possible to built with ICs, but it can also be designed by using a mosfet transistor and few other discrete components. The purpose of using mosfet in the circuit is because the mosfet is a voltage dependent device unlike BJT and other normally used transistors,
Hello Readers, We frequently add new circuit diagrams, so do not forget to come back often. Thank you.