This circuit was found in documentation from the 1970s. However, it can be implemented with modern transistors such as 2N2222 for Q1 and BF494 for Q2. The crystal depends on the desired frequency.
The component used in this circuit is uncommon today, as the circuit was obtained from Motorola's Linear...
This simulated circuit on the NI Multisim transmits modulated infrared signals with the audio...
This voltage sensor limits the discharge of a Nicad battery. We found it in an American...