LOW-COST PULSE DRIVER CIRCUIT For Solenoids And Coils

A pulse driver circuit designed for solenoids and coils generates a short pulse of predetermined width to activate the solenoid, regardless of the duration of the input drive signal.

- T.K. HAREENDRAN

This compact solenoid driver is useful for actuating solenoids in various devices and models, such as pinball machines or coil guns.

Fig. 1 shows a pinball coil lead, while Fig. 2 illustrates a drive pulse used in a pinball coil lead.

For details, refer to the links: https://en.wikipedia.org/wiki/Pinball for the pinball game and https://en.wikipedia.org/wiki/Coilgun for coil gun.

Circuit diagram and working

Fig. 3 presents the circuit diagram of the solenoid pulse driver. It is built around 5V voltage regulator LM7805 (IC1), CD4093 (IC2), optocoupler PC817 (IC3), MOSFET IRLZ44 (T1), and a 12V DC solenoid. The design is simple and self-explanatory, utilising standard budget components.

IC1 provides a regulated 5V output to power the circuit. The optocoupler IC3 sends a pulse to the NAND gates. The NAND gate monostable circuit, built around CD4093 (IC2), activates the solenoid.