Found in a 1968 EEE, this circuit accepts frequencies from 1 to 1000 Hz and control voltages from 0.1 to 15 V. The operational amplifier is from the era and can be replaced by modern equivalents.
This circuit was found in a 1980s telecommunications publication. The circuit uses a diode bridge to...
This circuit is from an English magazine from 1980, but it can be easily assembled with more...
The indicated circuit is an intermittent one in which we use two 555 integrated ones, one as a low...