This circuit was found in a documentation of the 80s, having didactic purpose. For R1 values between 10k to 1M can be used. Transistors are general purpose types.
Short pulses can be found in this 90's EDN circuit. The load is 50 ohms and the transistors are from that...
Found in an American 1980s documentation, this circuit generates frequencies in the range...
This old configuration of an audio amplifier has a push-pull two-transistor output stage. Output...