I would like to ask for help to build a circuit that is able to generate a square wave with a lower level of 20V for 1 ms and an upper level of 40V for 9 ms. It is quite challenging for me as it needs to handle high voltage and high current (up to 1A) as well. I have come up with a voltage-summing circuit to achieve the goal. One DC power supply is used as the lower level voltage and another DC power supply turns constantly on/off by a MOSFET timed by Arduino. Then with an opamp summing circuit, it should output a desired wave. However, it seems that this circuit can not pass a high current.

Please help me with this problem.


1 Answer 1


You can use a hit and hold circuit, these work for high current load circuits with solenoids:

enter image description here Source: How do I use a hit and hold circuit with a solenoid?

You need to specify the correct diode that can handle 1A of current. If you don't want to turn the load fully 'off' then for the lower voltage (20V) you could just connect that directly to the supply. Replace L1 with your load, if it's inductive you'll need a flyback diode, if it's not then leave it out.

  • \$\begingroup\$ Thank you so much for your help, I think this solves my problem nicely. I'm currently building this circuit and need some real test on it. \$\endgroup\$ Commented 12 hours ago
  • \$\begingroup\$ If you like the answer, use the voting system and mark the answer \$\endgroup\$
    – Voltage Spike
    Commented 11 hours ago

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