This circuit was found in a Ferranti documentation from 1969. The transistors are common types of the company at the time. Smaller equivalents may be used. The output power is of the order of 150 mW.
If you have a common analog multimeter, you can increase its input resistance in the measurement of...
This circuit was found in a Texas optoelectronic manual. Observe the polarity of the supply. Other...
This circuit is from 80s documentation and makes use of common operational amplifiers. The...