This simple general-purpose transistor mixer was taken from an article in Electronics Now magazine in March 1994. You can choose a low-noise transistor such as the BC549.
This circuit is from Motorola's Linear Interface ICs of 1993. The circuit can be powered by...
This circuit activates a relay when the supply voltage drops below the value set in the trimpot. The...
Based on National semiconductor power operational amplifiers, uncommon today, this circuit...