Found in a 1960s RCA manual, this circuit uses components from the era. For the indicated circuit R1 is 28ohm and R2 is 1 k.
We found this circuit in the Linear Applications Handbook of the National Semiconductor of 1994....
This tone-modulated transmitter was found in recent English documentation. The circuit operates in the 27...
This very low current circuit was found in the April 1995 issue of Electronics Now magazine. The...