Circuit Problem

Discussion in 'General Electronics Chat' started by crivoli, May 6, 2006.

  1. crivoli

    Thread Starter Member

    May 4, 2006
    Please help me!!!

    I have built the intercom circuit found at ( ), but it does not

    I have it connected to two 8 ohm speakers that I have used in another
    intercom circuit that worked.

    When I turn either switch on the corresponding BC558 transistor gets VERY hot!

    I took the audio transformers off to try it that way, but all that did
    was add extra noise on the line.

    I cannot see anything I have hooked up incorrectly. Do you have any suggestions?

  2. dbwgwee


    Mar 30, 2006
    Suggestion #1- Do NOT turn the switch on
    Suggestion #2- If you turn the switch on...don't touch the transistor
    Suggestion #3- Contact Jan H. and complain
  3. windoze killa

    AAC Fanatic!

    Feb 23, 2006
    What a helpful response.

    Now for some help. Did you connect the audio transformers the correct way around with the 8 Ω speakers? The schematic says "No 8 Ω without audio transformer". Having such a low resistance in the emitter of Q1 and Q3 would explain why the transistors are getting hot.