This circuit was found in RCA documentation from the 1980s. The circuit uses LDRs of the time and the 50 uA instrument has zero in the center. R1 and R2 may have 2k2 and R3 10k typically.
This circuit was found in a Popular Electronics of the 90s. It operates a third brake light that...
I found this little signaling transmitter in old American documentation. The circuit has a good...
This sensitive amplifier for low current measurement uses a differential amplifier configuration with...