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 timing circuit was found in old documentation. The technology is CMOS. The supply can be made...
This circuit was found in a 1967 General Electric documentation. Tunnel diodes can oscillate at very...
This circuit can be used in a signal level indicator with LEDs. The circuit is from an Electronics Now...