This circuit is from a 1969 Electronics World. The transistors may be modern general-purpose equivalents. The circuit is for frequency ranges between 250 Hz and 250 kHz.
This linear LED scale circuit was found in the February 1992 issue of Radio Electronics magazine. Note...
This circuit was found in an American documentation from 1969. The circuit is a multi-indicator with...
Found in a 90s Popular Electronics, this circuit is intended for amplifying analog video signals....