From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Specification sheet for an Adjustable Tuning Unit.
| Identifier | ExFiles\Box 138\1\ scan0308 | |
| Date | 1st April 1938 guessed | |
| SPECIFICATION OF ADJUSTABLE TUNING UNIT Type TF{T. Fisher}456 FREQUENCY RANGE The range of frequency to which the unit can be tuned exceeds 100 c.p.s. to 5 kc/s. STABILITY The resonant frequency for a particular setting will be maintained within 0.1% over long periods. EFFECTIVE RESISTANCE The effective series resistance of the series-tuned circuit varies between about 250 and 1,200 ohms over the whole frequency range. DYNAMIC RESISTANCE The dynamic resistance of the parallel-tuned circuit varies between about 30,000 and 200,000 ohms over the frequency range. INPUT VOLTAGE Series Connection : the applied voltage must not exceed about 20 volts at resonance, or 200 volts at frequencies far removed from resonance. Parallel Connection : The applied voltage must not exceed about 200 volts at resonance or higher frequencies, or about 20 volts at much lower frequencies. FREQUENCY CALIBRATION A calibration chart can be supplied to special order. MOUNTING All controls are conveniently disposed upon a vertical aluminium panel. The complete assembly is housed in a steel case with carrying handle. FINISH Panel—Black crackle lacquer. Case—Grey cellulose enamel. DIMENSIONS 12½" × 8" × 12¼" (over projections). 18½" × 14" × 18" (approx.) packed. WEIGHT 19½ lbs. nett. 48 lbs. (approx.) packed. PRICE See price list. SCHEMATIC ARRANGEMENT. PARALLEL SERIES | ||