This stereo meter-indicator was found in the August 1971 issue of Radio Electronics magazine. The transistors are known types and BC548 equivalents can be used.
A The adjustable Q-factor rejector filter in the figure is based on two LM110. These integrated...
This circuit can be powered by a voltage of only 2.5 V. Next to the diagram we have the formulas...
This circuit with a supply voltage of only 2.5 V was found in a 2005 Linear Technology...