This amplifier was found in a 1970s documentation. Darlington transistors can be replaced for modern equivalents of at least 80 V x 2 A, equipped with good heat sinks.
The figure below shows an AC transconductance amplifier with the National Semiconductor LM3900. The...
This common circuit using operational amplifiers was found in the 1993 issue of Radio Electronics Special...
This circuit provides a voltage at the output only when the input voltage exceeds a value that...