This 1965 Philips circuit uses old company transistors like the BFY51 and BFY50. The circuit is powered by 12 V and the power gain is 8.9 dB.
Texas Instruments' low power operational amplifiers OPAx196 can be found on Mouser Electronics....
This variable power supply uses common components and can supply a current up to 1 A. The...
This circuit was fond in an old publication of the years 1950. The transistors are germanium types and...