Been using a little square wave generator for experiments, has input
values from 3-29 VDC. However, at 24 VDC input, it burned out. I have
a replacement on the way, but vender suggested using a clamping circuit
to limit voltage to 25 VDC if my power supply is prone to spikes and I
suspect it is. Can someone suggest a suitable circuit with component
values needed? Thank you.