User manual

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Fig. 29: Setup with R- and S-button
9 Flash Circuit
Two NAND gates, two resistors and a capacitor can be used to build an
astable flipflop that independently switches back and forth. Like am RS
flipflop, a feedback is used here. A condition is, however, only stable for
as long as the capacitor is being charged. Then the starting condition
changes. Strictly speaking, this is not a digital circuit because the input
voltage of the left gate changes slowly. In the end, however, a digital
signal occurs at the output and changes periodically.