I am looking for input on this circuit that I have designed. I am currently working on a project called the Net-EEL RC Car. It is an RC car that will be controllable using Network Socket Servers / Clients. Therefor, you will be able to control an RC car sitting at the network server with a gaming steering wheel.

I am trying to design my H Bridge circuit to control the speed and direction of the motor I will be using. I am using the Raspberry PI as my Data Receiver and will be using the PI to control the H Bridge.

Here is a schematic I have designed. enter image description here

So far I have the following

  1. Raspberry PI will generate PWM signals to control a BJT. This BJT is used to control a Mosfet. I have chosen a BJT due to the VGS requirements of a Mosfet. It requires me to supply a gate voltage that is equal to the source I am controlling, therefor I am using a BJT to apply the source voltage to the gate of the Mosfet.

    I have looked into to using Logic Level Mosfets, which will remove the need to use BJT's in order to provide a proper gate voltage to the Mosfets.

  2. I also have a Micro controller that will be used to monitor the voltage level of the battery, I am running the battery voltage through a voltage divider so I can properly read the voltage level using a 0-5V ADC.

I believe that my circuitry will work, however I am looking for some input from the community.

Thanks in advance.

** EDIT ** I have added the resistors between the Gate of the Mosfets to ground in order to turn off the transistors if there is no signal present at the BJTs base.

** EDIT 2 ** I have also considered using logic levels mosfets instead of needing a BJT.

  • \$\begingroup\$ Do you have a specific question? \$\endgroup\$
    – Null
    Commented Dec 17, 2014 at 22:35
  • \$\begingroup\$ you have nothing to turn OFF the NTypes or turn ON the PTypes. This circuit will not really work \$\endgroup\$
    – user16222
    Commented Dec 17, 2014 at 22:37
  • \$\begingroup\$ @JonRB If I understand what you are saying, It seems like I have missed the resistors between the Gate of the mosfets to ground in order to turn them off if there is no signal applied. \$\endgroup\$
    – Eric E
    Commented Dec 17, 2014 at 22:44
  • \$\begingroup\$ @Null No, there isnt a specific questions. I am more so looking for inputs from the community on the design and whether it would work. \$\endgroup\$
    – Eric E
    Commented Dec 17, 2014 at 22:45
  • \$\begingroup\$ Very pretty diagram. I especially like your use of colour. Nice and eye catching. \$\endgroup\$
    – Majenko
    Commented Dec 17, 2014 at 23:36

1 Answer 1


Why are you not driving the motors directly by L293D? Its a reliable working H-Bridge and also the it can make your circuit less troublesome..

There are other ICs avaliable for H-Bridge based on persons requirements..

  • \$\begingroup\$ I am building an H bridge because It is a requirement to build your circuits instead of using ICs. Not like it is difficult to build a proper working H bridge \$\endgroup\$
    – Eric E
    Commented Dec 18, 2014 at 19:46

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