H-Bridge with 4 Transistors and varible voltage

This is surprizing full of pitfalls - each transistor needs to be in the switching configuration, meaning common-emitter, and this requires the top two transistors to be PNP.

Secondly you need to be able to drive the top two PNP transistors, often needing level-shifting (two more transistors).

Thirdly you must arrange to completely avoid any chance of shoot-through - you need to allow dead-time between switching off a lower transistor on an arm of the H-bridge before switching on the upper transistor (& vice versa) - transistors take time to switch off, often in the 1 to 5µs range, and the naive way to drive a bridge won’t allow for this.

You’ll learn a lot making an H-bridge, but expect to make mistakes if you don’t think carefully about what’s going on.


@ MarkT
Yes, I realize that it’s not an easy start into the arduino world. But I usually end up not with easy tasks, no matter what I do^^

shoot-through can be avoided with proper coding, no? Or I could take two transistors on the same I/O, so there is no chance mixing it up?

I had a look at the resistance of BJTs and think that I need some MOSFETS. R_DS is much smaller (in the range of 0.1 Ohm).

No I’m trying to find out how a simple high side switching circuit using a MOSFET works.


This H-Bridge from Amazon unfortunately only works with 12V.