Despite being from a 1969 publication, the transistors used have current equivalents such as BC548 and BC558. The circuit generates signals from 1 500 to 20 000 Hz and 4 scales.
This circuit, from the 1990 Motorola Dataar Databook, can use any LM139 series comparator. The circuit...
We find this circuit in a 1980s documentation for amateur radio. The circuit shows how to switch...
With this circuit found in a 1965 Electronic Design, it is possible to read a peak voltage of up to...