Transformerless circuit add an Isolation transformers.

Discussion in 'General Electronics Chat' started by ripperpc, Sep 17, 2017.

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  1. ripperpc

    Thread Starter New Member

    Sep 17, 2017
    This is an old thread but trying my luck here.

    I have built a project using something similar to this circuit :

    I am aware of the dangers of using it, and it will be full encased when in use.

    I would like to check the voltage ripple, voltage under load. To that effect I recently purchased an isolation transformer.
    Assuming I have connected the DUT through the isolation transformer.

    Where should I connect the GND lead of the oscilloscope to see 6.2V on the scope ?


    Mods Note:
    Please don't hijack other member's thread, now you have your own.
    This thread was split from Isolation transformers "no" says Tektronix.
  2. ScottWang


    Aug 23, 2012
    Please redraw the new circuit, otherwise this thread will be closed.
    And are you trying to using the transformerless circuit in the real world?
    If the answer is yes then this thread also will be closed.
  3. GopherT

    AAC Fanatic!

    Nov 23, 2012

    Stepping down AC voltage without a transformer means your circuit has to divide the voltage (either with a resistor (resistance) or capacitive reactance (capacitance)). In the divider, one side is your fixed resistance or capacitance and the other side is your load.
    In these designs, you'll need to know the current draw of the load to determine the voltage divide. These are dangerous because there is no isolation. So dangerous that this site bans discussions of these circuits. You seem to understand that because you mention adding an isolation transformer to it.

    If you are going to add an isolation transformer, you may as well use a step-down isolation transformer and eliminate the existing circuit all together. Once the isolation transformer is installed, there are very easy and safe methods to regulate the voltage.
    Last edited: Sep 17, 2017
    ScottWang and DickCappels like this.
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