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.
Found in a 1964 Electronic Design this circuit compares two signals by providing the inverse of the...
In the figure we have a voltage follower for AC signals. We found it in the Radio Electronics...
This is the 4013 CMOS configuration as a flip-flop to divide the frequency of a rectangular signal...