This configuration is from the 70s, having been found in an American documentation. The transistors can be BC549 for Q1 and BC548 for Q2.
This high-gain digital amplifier uses general-purpose transistors. The supply voltage is logic...
We found this circuit in the March 1993 issue of Electronis Now magazine. The circuit uses common...
Using an LDR as a sensor and an operational amplifier this circuit was found in the Encyclopedia of...