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.
Using the CMOS 4001 we found this circuit in the October 1974 Radio Electronics magazine. The...
One 4018 is used to divide the frequency of a digital signal by ten as shown here. The maximum...
This 90's project shows how to use an old cassette recorder to practice telegraphy. In position A of the...