Found in an English publication from the 1980s, this circuit can be built with equivalent transistors such as the BC549. The signal must be applied to an external amplifier.
We found this digital timer circuit in a 1994 publication. The power is supplied by 12 V, which is the...
We found this circuit in the 1982 SGS Linear Integrated Circuits manual. The transistor supports...
This simulated circuit on the NI Multisim transmits modulated infrared signals with the audio...