This circuit is from a time when this type of feature was not common in line cars. The pulse transformer has a 1: 1 turn ratio and the SCR admits equivalents.
This circuit was published in an English magazine from 1980. The magazine no longer exists, but...
This circuit provides precise signals of three frequencies, using CMOS technology. The integrated...
This is the power supply for the amplifier in the previous circuit. The voltage regulators must be...