We found this circuit in American documentation from the 1980s. Transistors can be of general use. The frequency range of the generated signals ranges from 500 kHz to 10 MHz.
This receiver for infrared remote control was found in the Philips Databook of 1990, The circuit...
Found in an English publication from the 1980s, this circuit uses components that are still common...
This circuit was found in Maxim's documentation from the 90's. The frequency of the circuit is...