Club de Arduino – Week 2: Building an H-Bridge

H-bridge prototype on breadboardToday we tried to build an H-bridge to control the motors.

An H-bridge is a circuit that makes it easy to control a motor to go backward or forward, for example from an Arduino.

We used TIP120 and TIP127 transistors and built the following circuit using 5V as VCC:

H-bridge circuit using BJT transistors with diode protection

It did not work.

We are not sure if there was a problem with the connections – or if the circuit design itself as the problem.

What’s next?

Until next time, I will check the connections of the circuit and do some measurements. Eduardo will look at simulations to see if he can find any problems with the circuit there.

We’ll meet up in one week to continue building the robot.

Check out week 3 of the build >>

Go back to the overview of Club de Arduino

More Arduino Tutorials

2 thoughts on “Club de Arduino – Week 2: Building an H-Bridge”

  1. nope; the Vce and Vbe of the tip120 is too high to run it on 5V like this; both transistors are saturated above 2Vce, leaving you with less than 1V across the motor, if any.

    the arduino does not have the current to drive these transistors either.

    at this low voltage, BJTs aren’t going to be very helpful. even low saturation transistors have a Vce around 700mV to 1V.

    look at using a L293 IC to drive instead, or look at how 7V remote control cars use a mosfet HBridge to run their motors

    • Yep. That’s what I found too. Only 1V left for the motor. I found a cheap H-bridge module at a local shop here, so we’re gonna use that one.

      But would like to make it work, so I have to take a look at the transistor selection at the local shop to see if I find something suitable.



Leave a Comment