## How do I measure output impedance?

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Reply #4 –

You need: 60 Hz sine test signal, digital multimeter, dummy load.

Measure the voltage unloaded and with dummy load.

Calculate:

Zout = (Rload * (Vnoload - Vload)) / Vload

Example:

We measure 1V unloaded, 0.9V loaded and our dummy load is 30 ohm ==> (30 * (1 - 0.9)) / 0.9 = 3.33 ohm output impedance at 60 Hz.