This low power circuit was obtained from an American 80's documentation. The circuit indicates the voltage of a battery being trimmed by the trigger point. The transistors can be the BC549.
This circuit was taken from an article in Electronics Now magazine in February 1995. The power...
Found in a Hands On Electronics from the 80's, this circuit activates a relay with alternating...
This circuit was found in a publication of the year 1968. It uses complementary transistor to...