This compact power supply can be used on the workbench for up to 1 A load. The transformer has 1 A secondary current. The integrated circuit must be mounted on a heatsink.
This circuit was published in a 1977 Radio Shack catalog. The PNP transistor may be BD135 and NPN...
Texas Instruments Standard Operational Amplifiers Texas Instruments makes available through Mouser...
This circuit produces an intermittent ring tone being triggered directly by the telephone line. However,...