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 a publication by Newton C. Braga in the United States. The transistor can be...
The circuit is from the Texas Instruments optoelectronics manual. The capacitor depends on the...
This circuit was found in an application note of the LTC1164 from Linear Technology of the 1990s....