We found this circuit in a Philips documentation from 1965. The circuit uses a common LDR sensor and the transistors are general purpose types. TR2 can be a BD135.
This circuit shows on the screen of an oscilloscope two signals alternately at a frequency that depends...
Using a sensitive reed relay (20 mA or less) it is possible to drive a high-power load from TTL...
This power control circuit was found in an article in the June 1995 Electronis Now magazine. The...