1311-A

The General Radio 1311-A Audio Oscillator, a transistorized Wien-bridge audio oscillator with transformer output, was introduced in Catalog R (1963) and remained available through Catalog 1978.

The switched output frequencies correspond to commonly used bridge generator frequencies. A delta frequency control is available on the front panel to fine-tune the frequency. Although designed as a bridge oscillator, the 1311-A is also well suited for audio testing, given its low hum and distortion levels.

The 1311-A is part of the 1240-A Bridge Oscillator-Detector. As a bridge oscillator, it is part of the 1660-A Inductance Measurement System and the 1620-A Capacitance Measurement System.

Specifications

• Frequency Range: 11 fixed frequencies selected by rotary switch – 50, 60, 100, 120, 200, 400, 500 Hz; 1, 2, 5, 10 kHz; ±2% vernier
• Power Output: 1 W into matched load; taps provide at least 0.5 W output into any resistive load between 80 mΩ and 8 kΩ
• Output Voltage: Continuously adjustable from 0 to 1, 3, 10, 30, or 100 V, open circuit
• Output Current: Continuously adjustable from 0 to 40, 130, 400, 1300, 4000 mA, short circuit (approx)

Links

• Experimenter August 1962 describing Type 1311-A
• R.G.Fulks, Novel feedback loop stabilizes audio oscillator; Electronics Vol.36 No.5, 1 Feb 1963.

Photos

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  Late model, white front-panel 1311-A as part of a 1240-A