Current indicator (CB22132E)

In this circuit the voltage across the LED is limited by the diodes. The maximum current also depends on the resistor.

Temperature Compensated Crystal Oscillator (CB6144E)
This circuit was obtained from Linear Technology documentation from the 80's. Powered by 5 V it...
10 to 100 seconds time switch (CB20371E)
This circuit was obtained in a documentation from the 1970s. What it does is to delay trigger a...
Debouncer 555 (CB11564E)
In the figure we have an anti-ring or debouncer circuit with 555. The duration of the pulse is...