preamplifier overvoltage, reverse polarity protection

Discussion in 'General Electronics Chat' started by masudasim, Jun 25, 2011.

  1. masudasim

    Thread Starter New Member

    Jul 10, 2010
    Hello all

    I have designed a preamplifier which operates on unipolar supply +10V and draws about 20mA to 40mA depending upon jumper setting.Now i need to add reverse polarity protection as well as overvoltage protection (maximum allowable voltage is +15V)

    Kindly tell me is there any simple solution available?

    Best Regards
  2. tom66

    Senior Member

    May 9, 2009
    It depends on what you mean by simple.

    A circuit that uses the LTC4365 can do this, but it is an SMD IC, using an SMD MOSFET and a few other SMD components - in other words, it can be tricky to solder.

    A 15V zener across the supply with a fuse in line will blow the fuse if the voltage exceeds 15V or drops below -0.7V, but you will need to replace the fuse every time someone does this.
  3. #12


    Nov 30, 2010
    This same question just came in on a homework job.
    Use a full wave bridge rectifier on the power input so it always routes the polarity correctly, then do the over voltage protection. The "simple" way is the fuse and zener.