This circuit was found in a 1970's Radio Electronics. The pulse transformer has a 1: 1 turn ratio. The triac must be in accordance with the controlled load.
With the use of a cascade transistor, the dynamic response of a phototransistor can be increased, as...
In the figure we have an oscillator with a single transistor that can generate signals in the...
This source was found in Philips' 60s documentation. The transistors are from the era and the...