Using an operational amplifier, this circuit from a 90s Popular Electronics, is characterized by its high sensitivity. R5 can be added to control the gain.
This transistor radio was manufactured in the 60s and has 6 transistors from that time. The...
This circuit makes use of a transconductance operational amplifier. It generates signals with TTL...
This circuit was found in a Popular Electronics of the 1980s. The microammeter may be the lowest...