This circuit is from American documentation from the 1980s. The transistors are general purpose types and the relay can be 6 or 12 V depending on the supply voltage.
This transformerless circuit was obtained in a 1965 publication by Ferranti. The components are from...
This circuit is based on an old Siemens integrated that can now be found very easily. It allows the...
The 4047 is a monostable/astable CMOS multivibrator. The basic con- figuration is triggered by the...