Based on the BA1404 integrated circuit, this circuit was found in the July 1992 issue of Radio Electronics magazine. The circuit is short range, but a power amplifier stage can be used.
This circuit, in addition to providing an output that corresponds to the absolute value of the...
We found this circuit in a 1968 Electronics World. The transistors are from the era and...
This circuit was obtained from an internet documentation. The LED is inverted in the original, and the...