Help configuring radio controlled h bridge solenoid circuit

Discussion in 'The Projects Forum' started by jgeidel1022, Oct 29, 2015.

  1. jgeidel1022

    Thread Starter New Member

    Oct 29, 2015
    I am working on a project to control a latching solenoid via radio control. The solenoid is a dual position solenoid using a magnet to latch in the retracted position. The solenoid will not work properly unless current is limited to between 0.75 and 1 amp. It's resistance is 3.3 ohms so it naturally wants to draw upwards of 4 amps from a 12 volt source. My knowledge of electrical components is not very deep but I took some courses in college and have a general knowledge of basic circuits.

    I am planning to use a 2 channel RF receiver in combination with an L293 quadruple Half H-Drive to control the solenoid.

    I am concerned with limiting the current to a value between 0.75 and 1 amp and do not know an effective (or generally acceptable) method of doing so.

    My thought was placing the whole circuit as a load on a transistor which I will size a base resistor accordingly to supply only 1 amp through the emitter. I am in a little over my head at this point and any pointers would be greatly appreciated.

    I have attached a drawing for reference.

  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    How long does the solenoid have to remain powered after its initial pulse?
  3. jgeidel1022

    Thread Starter New Member

    Oct 29, 2015
    Momentarily. <1 second probably more in the 0.25s to 0.5s range.

    Edit: The duty cycle will be very low. Activated once every 30 minutes or so
  4. MaxHeadRoom


    Jul 18, 2013
    A typical RC Li-Po battery supplies many amps for motor and servo's that load would be trivial for even a small size.