I am currently designing my own H bridge and have decided to start of with a very basic circuit consisting of 4 NPN transistors (2N2222A) which I have attached a circuit of:
It seems to work OK, with control signals A and D used to turn on the “forward” direction, and B and C to turn on the backward direction (all control signals via base current limiting resistors from the Arduino digital out pins).
Testing the motor independently, it speeds up when the voltage across its terminals is increased from 5V to 12V.
However, with my H brdige, the motor does not speed up when VCC is increased from 5V to 12V. It stays the same speed!
What is wrong with this circuit, and does any one have any tips for H bridge design?
Do I need PNP high side transistors? Will this solve the problem?
Thanks for any advice!