Power Supply DC-ripple measurement

Discussion in 'General Electronics Chat' started by dukeman, Oct 23, 2014.

  1. dukeman

    Thread Starter Member

    Feb 7, 2009
    I have few questions about measuring dc-ripple on a power supply using a scope according to the procedures on Rufus Turner's Practical Oscilloscope Handbook:
    1. Can I directly connect the dc output of a power supply to scope and measure the ripple voltage?
    2. According to Turner, one can put a load in between the power supply and oscilloscope, measure the dc-ripple voltage. Can I use a 50 ohm dummy load to do that?

    Thanks for your insight in advance.

  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    Connect a DC load (resistor, whatever) across the power supply. Connect the scope across the supply, likely ground clip to - and probe tip to +. Put the scope in AC volts mode, and turn up the gain to a few mV per division. Read the ripple as an ac voltage, peak to peak. That is the ripple value. Try disconnecting the DC load while watching the ripple...