A brushless DC motor driving experiment based on 74HCT238 decoder for beginners

An simple and novel experiment for brushless dc motor (BLDC) driving is proposed. It uses a 74HCT238 decoder combined with 6 photocouplers, 4 operational amplifiers and 3 comparators to decode the position signals from the hall devices and does not need any digital chips or special BLDC driving ICs to generate the driving signals. It directly uses the 5 V power supply from a running PCpsilas USB port to power the whole experiment without the need for any dedicated power sources. The experiment is very cheap and can still demonstrate the BLDC driving principles very well. Students can get all the required electronic components from any electronic component stores, setup the circuit on breadboards and make the BLDC running easily. In that way, the beginners who need to master BLDC driving can gain feeling of achievement and joys very quickly, it can help them to bring up interests to make further research in motor driving.