You supply the timer NE555 through the Pin1 (GND) and Pin8 (Vcc) with power. In your experiment, you use a voltage of Vcc = 9 V.
Circuit diagram power supply for an NE555. |
Internal circuit diagram of a NE555 with power supply |
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Between the two terminals of the power supply, there are three identical resistors which function as a voltage divider and provide the following voltages...
These voltages provide the reference voltages for the trigger and threshold input. You come back to these voltages in the experiments 4 and 5. |
Circuit of the power supply of the NE555. (Enlarge) |
