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568 items

AC Voltmeter with Case

3-15 Volts AC Pattern No. 11

AC Voltmeter

0-130 Volts AC, 25-125 cycles/sec Model 155

AC Ammeter

0-3 Amperes AC Model No. 155

Phasemeter

Phasemeter 0-180 degrees Model 100A

Multimeter with DB Scale

volt-amp-ohm meter with DB Scale Model 900 A

Wheatstone Bridge

Cat. No. 4725

Ammeter

0-50 Amperes DC

Ammeter

0- 500 Amperes DC Model No. 1

AC Ammeter with Case

0-1 amperes AC

AC or DC VoltAmmeter

0-100 Milliamps, 0-30 Volts Model A, Poly-Ranger

DC High Impedance Voltmeter-Null Detector

-10 to + 10 Volts Model 845AB

Clamped Square and Round Brass Vibrating Plates

This apparatus came with the holder and two brass plates, one round and the other square. The plates could be made to vibrate, perhaps by stroking with a violin bow or tapping with a mallet, and the resulting sound examined. They could also be mounted with the plate horizontal. Then if a light powder, such as lycopodium powder, was placed on the plate, the nodes of standing waves in the plate when it was bowed or tapped could be seen in patterns of the powder.