switch one load off whilst switching on another

Discussion in 'General Electronics Chat' started by gdallas, Oct 17, 2014.

  1. gdallas

    Thread Starter Member

    Apr 25, 2012
    74
    0
    under normal conditions my main load is R4, however when my PWM becomes capable of switching on my FET, and hence my lamp (R3) What would be the best way to siwtch off R4 at the point my FET swithces on to alow current to flow through R3. the loads will be matched in the final circuit, both 6 ohms.

    thanks
     
  2. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,516
    1,246
    Without knowing anything about the needed response time, cross-conduction, etc., it's hard to say. Based on the information you're given, a simple frequency discriminator (missing pulse detector) driving a SPDT relay will work.

    ak
     
  3. gdallas

    Thread Starter Member

    Apr 25, 2012
    74
    0
    hi,

    do not want to use relays. poewrfets or similar only. The frequency is constant, 100Hz. the fet shown switches on at around 50%, my thoughts were a a matched P channel FET but unsure if this would work and if it would, how to configure it,
     
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