User manual

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19 Simple RS flip-flop
A very basic flip-flop can be built with just one LED and three
resistors. The two buttons are used to switch the LED on and
off. Such a circuit is also called RS flip-flop. The abbreviation
stands for Reset (reset = switch off) and Set (set = switch on).
The RS flip-flop is an important element in digital electronics
and computer technology.
The two-transistor circuit is again based on the fact that each
transistor can turn off the base current to the other transistor.
Because we are only using one LED, you may be interested in
testing out the other colors too. You can remove an LED that
is turned on and replace it with a different one. After the LED
is replaced, the newly connected LED will go on first. Because
when you remove an LED, you also switch off the base cur-
rent for the left transistor. That is like you were switching the