1214-D
The General Radio 1214-D Unit Oscillator was introduced in Catalog P (1959) and remained available through Catalog S (1965), an updated version of the 1214-AS2 (1956).
The Type 1214-D is a unit oscillator specifically designed as a generator for the Type 1611-B Capacitance Test Bridge. It operates at 120 Hz, the recommended frequency for testing electrolytic capacitors.
The 1214-D output circuit uses two transformers, the first serving as a load for the oscillator tube, and the second acting as an adjustable match for the Type 1611-B bridge. A front-panel phone jack acts as an input to the matching transformer for an external oscillator.
A single 117N7 tube contains the power supply rectifier and a beam PA as the oscillator. A Thyrite element (varistor) is used in the 117N7 grid circuit to limit oscillator amplitude. Like other instruments in the 1214 family (1214-M, 1214-A, and 1214-E), the 1214-D's power supply is transformerless.
Specifications
- Frequency: 120 cycles ±2%
- Output Impedance: Four impedances to match the impedance of the Type 1611-B Capacitance Test Bridge at four multiplier positions
- Output: At least 2000 mW into matched load
- Distortion: Less than 3% into a matched load
