Abstract: A voltage monitor is disclosed. The voltage monitor comprises a digital voltmeter for displaying a measured input voltage, and means for converting the varying input voltage of the monitor into a stabilized power supply voltage for the operation of the digital voltmeter. The input voltage is applied to the digital voltmeter through a response time controller providing a long time constant averaging value of input voltage to the digital voltmeter when the input voltage is within a predetermined range about a normal value, and for providing a faster response to input voltage values when the input voltage exceeds its normal value. The voltage is also applied to a stability indicator through an averaging circuit which permits the stability indicator to show short term fluctuations of input voltage about its normal value.