Found in a Motorola documentation from the 70s, this circuit makes use of transistors of the time. Modern equivalents can be used. The diode also supports an equivalent.
The traditional circuit was taken from a French magazine Radio Plans that no longer exists but can...
This circuit was found in an 80's Radio Electronics. The circuit multiplies the frequency of a low...
This circuit makes use of a 741 single source operational amplifier to measure resistors on a...