Keyestudio ARDUINO maker learning kit, Manual

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Project 34: NE555 Timer
Introduction
If you ask anyone in the know to rank the most commonly and widely applied integrated circuits,
the famous 555 time base integrated circuit would certainly be at the top of the list. The 555 – a
mixed circuit composed of analog and digital circuits – integrates analogue and logical functions
into an independent integrated circuit, and hence tremendously expands the application range of
analog integrated circuits. The 555 is widely used in various timers, pulse generators, and
oscillators. In this experiment, we will use the Uno board to test the frequencies of square waves
generated by the 555 oscillating circuit and show them on a serial monitor.
Hardware required
Uno board *1
USB cable *1
Breadboard *1
NE555 *1
104 ceramic capacitor *2
Potentiometer (100KΩ) *1
Resistor (10KΩ) *1
Jumper wires
Circuit connection
The 555 integrated circuit was originally used as a timer, hence the name 555 time base circuit. It
is now widely used in various electronic products because of its reliability, convenience, and low
price. The 555 is a complex hybrid circuit with dozens of components such as a divider,
comparator, basic R-S trigger, discharge tube, and buffer.
555 chip pins are introduced as follows: