This sound relay or Vox was found in 70s RCA documentation. SCRs can be common types today and transistor a BC558. The circuit is for the 110V power grid.
The circuit shown in figure 1 uses the ST8R00 from ST Microelectronics which consists of a 1 A...
This is the conventional application of a 1 out of 10 decoder with CMOS 4017, as shown in an old...
We found this third-order Butterworth asymmetric filter in an old manufacturer documentation. The...