The transistors of this circuit found in a 1965 magazine can be the BC558 and the sensitive 12 V x 50 mA relay. The other components are common.
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...