Voltage Measurement

DC Voltage

A voltage divider can be used to measure a voltage with a microcontroller (MCU), but it is much better to use a high impedance circuit to minimize influence of the measurement on the circuit being measured. Implementing a high impedance circuit will draw nearly no current from the circuit being measured.

An op-amp with a voltage divider consisting of low output resistance (1M ohm) resistors is a good choice. Use the LM324 for DC low frequencey, and the TL082 for AC projects involving audio or higher frequencies. In the 'related links' section below, you see John Errington's circuits using the MCP6042 and other op-amps.

AC Voltage

Voltage Transformer VT (or Potential Transformer, PT) is a device that converts the high voltage of an AC circuit to a lower voltage. Beware of the effects of electromagnetic induction on your measurement.

Under Development

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