This circuit uses the LM2931 which is not a common component today. What it does is to activate a lamp causing it to blink at a frequency determined by the capacitor.
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This very simple circuit with neon lamps indicates who pressed the button first, lighting the...
The circuit in the figure is a comparator for negative voltages, and a pair of polarization...
This simple timer, which activates an LED indicator, but which can be modified to activate a...