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I have a device that can be configured to maintain a specific bias voltage on the output. How should I verify if it actually generates that specific voltage?

I do not think I could simply use a multimeter to measure that voltage. Instead, I thought I should use a resistor on the output of that device and then measure the voltage across it. Is that necessary?

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  • \$\begingroup\$ What is the 'bias voltage' to be used for? It might make sense to measure the voltage with a load or not, depending. Or maybe over a range of possible loads. For example, for a photodiode the current drawn might vary from almost nothing (pA) to hundreds of uA. \$\endgroup\$ – Spehro Pefhany Jun 26 '18 at 23:19
  • \$\begingroup\$ The “bias “ impedance will drop according to probe impedance divider which may be ok. \$\endgroup\$ – Sunnyskyguy EE75 Jun 26 '18 at 23:34
  • \$\begingroup\$ @TonyStewartolderthandirt are you referring to oscilloscope probe? I tried measuring with oscilloscope, but the measured voltage drifts quickly to zero. Why is that? \$\endgroup\$ – Nazar Jun 27 '18 at 12:29
  • \$\begingroup\$ Is it AC coupled ? Or incorrect operation . Sounds like it. Measurements require schematic and purpose of test. Pls update question \$\endgroup\$ – Sunnyskyguy EE75 Jun 27 '18 at 15:52
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If your goal is to measure the no-load voltage, for most cases you can simply use the multimeter. When set for "DC volts", a multimeter already contains a built-in resistor in the megaohms range, so only a tiny amount of current will be drawn from your output. Unless your circuit is very sensitive or is operating in the microamps range, the current drawn by the meter will have a negligible effect. If you add your own load resistor, its resistance will be in parallel with the meter's own internal resistance.

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