An Electronic Phasemeter

The instrument described is designed to read and record directly on calibrated scales the phase angle between two sinusoidal voltages having a voltage range of 1 to 30 volts, over a frequency range of 100 to 5,000 cps to a sensitivity of 0.5°. The separate sinusoidal input voltages are converted to square waves through cascade amplifiers and limiters, and applied to two separate phase indicators. One indicator is ambiguous about the 180° value and measures and records the average of the algebraic sum of the square waves in the separate channels. The second type of indicator is unambiguous, and is operated by differentiating the square waves and applying the proper resultant pulses to fire a trigger circuit of the Eccles-Jordan type. The average plate current in the trigger tubes is directly proportional to the phase angle between the two input voltages to the phase meter.