This site is a free non-profit repository of materials from GAP/R George A Philbrick Researches, the company that launched the commercial use of the Operational Amplifier in 1952. The Philbrick Archive and Operational Amplifier The first commercial Operational amplifier was the K2-W op-amp. It was based on the amplifier used in the Philbrick modular Analog-Computor [...]
Archive of posts tagged Olden-Circuits
Voltage regulator 15V 5A Dual Supply
The fig. 6.2 shows the circuit of a regulated power supply for +/- 15 V and 5 A. The output voltages are adjustable between 12 and 17 V. A tape-wound core transformer is used. It offers a better power-to-volume ratio than conventional ones with laminated cores. The voltage control is achieved by two series transistors, [...]
Parallel Controlled Power Supply
Parallel-controlled circuits operate as self-controlled, variable resistors, connected in parallel to the load impedance (parallel loads). They react extremely fast and also control immediately pulses and very short mains break-downs, resulting from strong loads. These devices are preferably used in TV receivers, which have a B-class operated audio output stage. Without any parallel control the [...]
Antenna-amplifier with BFT 12 for FM-range
The only way to improve the reception of FM-signals or particularly of stereo FM-signals under disadvantageous receiving conditions is to amplify the antenna signal. This should be made directly at the antenna, since the loss is increased meter by meter of any cable. In most cases higher line attenuations can be expected than usually calculated. [...]
