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Some questions

Discussion in 'General Electronics Chat' started by naveed, Sep 8, 2012.

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  1. naveed

    Thread Starter Active Member

    Mar 12, 2008
    I have a few questions regarding this circuit:


    1. There is no step-down transformer used in the circuit, is voltage being dropped? and how (if yes)?

    2. On the base of Q1 (BC558) high voltage is applied, why a big resistance is not used here?

    3. when the voltage is applied to the transister's base, it must start conducting between emitter and collector. Isn't this transister doing reverse job?

    4. Can I use a relay instead of LEDs to run high power AC moter? In this case how much power this circuit will take including relay?
  2. ecesoul

    New Member

    Sep 8, 2012
    1. No step down transformer is needed.The capacitive reactance in series with AC supply will do that job.The combination of series cap,bridge rectifier and another cap parallel to it will act as a good step down source.

    2.I dont think high voltage will go to base of that transistor, due to above reason
  3. bertus


    Apr 5, 2008

    I am closing this thread as it violates AAC policy and/or safety issues.

    One of the main problems is the direct connection to the mains power.
    The capacitor can fail.

    An isolation transformer is a must for safety.

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    • Automotive modifications
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    • LEDs to mains
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