This circuit is from an American transistor book from the 60's. The transistor is germanium of the time.
This circuit is from a Popular Electronics from the 90s. Its gain is 22 dB and can be used as a...
We found this circuit in a 1995 publication. It makes use of infrared LEDs of the type existing at...
This circuit is activated by the ignition key which, when removed, makes a relay beep if the...