A Thermionic Type Frequency Meter for Use up to 15 kc

A new type of frequency meter is described which is adapted to the measurement of low and intermediate frequencies. The instrument absorbs a negligible amount of power from the circuit being tested, has a linear calibration curve and a sensitivity of about eight microamperes for one per cent change in frequency. An experimental model is described in detail. The input to this model is between five and ten volts. Other models may require different inputs.