I created a mosfet h bridge based on the design from bristolwatch.
I'm using it to power a solenoid (that needs +24v or -24v to open/close a valve). If I connect the solenoid directly up to my 2200uf capacitor, I can get it to turn on/off. But when I connect it through the h bridge, it doesn't appear to be getting enough power (a multimeter on the capacitor shows it only draining halfway). I've tried using a 10k, 30k, and 100k between the source-gate of the p channel mosfet, but none appear to be working. Q5/6 are PN2222ATF powered by a pi. (slight modification is a 100k between the base-emitter, but I'm pretty sure I've tried it with and without this)
My hunch is that it has to do with the gates not getting enough power to open up my mosfet enough for 5a. The gate threshold voltages are 1-2v (N) and 2-4v (P), but I'm not really clear on whether that is a difference of 1-4v from my 24v or 1-4v total. And I can't figure out how to calculate the ideal resistor for gate-source and if i need a separate resistor for my n channel gate since it has a lower threshold.
Thanks for any help!