This circuit was found in a Signetics documentation from the 1980s. The integrated is a PLL and the SCR is a general purpose type The pitch frequency is given by R1 and C1 as formula next to the diagram.
This excellent circuit came out in a Japanese publication from 1971. It uses Japanese transistors of the...
This circuit is from the owner's manual of the integrated circuits used. The manual is old, which...
We found this circuit in an English documentation from 1995. The Hall sensor used is from the time...