546-C
The General Radio 546-C Audio-Frequency Microvolter was introduced in Catalog L (1948) and remained available through Catalog T (1968).
It is an audio-frequency voltage divider and attenuator, an updated version of the earlier 546-B with changes being improvements to the meter, and adoption of the 600 Ω impedance standard for audio applications.
The primary application of the 546-C is to supply audio-frequency voltages at attenuated and calibrated levels, but it can also be used to measure unknown voltages by "Substitution" and "Insert-Voltage" methods.
Any audio oscillator that can supply 2.2 V into 600 Ω will be sufficient to drive the Microvolter.
Specifications
- Output Voltage Range: 0.5 μV to 1.0 V, with 2.2 V input voltage
- Accuracy: For open-circuit output voltages, calibration is accurate within ±(3% + 0.5 μV) for output settings above 1 μV and for all frequencies between 20 and 20,000 Hz
- Output Impedance: approximately 600 Ω ±5%
- Input Impedance: approximately 600 Ω
