555: Rozdiel medzi revíziami
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| Riadok 17: | Riadok 17: | ||
C1 is measured in Farads, R1 & R2 are in Ohms, so for values in schematic: | C1 is measured in Farads, R1 & R2 are in Ohms, so for values in schematic: | ||
| − | T = 0,693 × ( 100 000 + 2 × 100 000) × 0. | + | T = 0,693 × ( 100 000 + 2 × 100 000) × 0.000001 = 0,2 seconds (or 4,8 Hz) |
If you want a different frequency, you would change the values of C1, R1 & R2. Changing the capicitor is the easiest to imagine -- if you go from a 10 µF capacitor to 1 µF, it will take 1/10 the time to charge, so your frequency will go up by a factor of 10. | If you want a different frequency, you would change the values of C1, R1 & R2. Changing the capicitor is the easiest to imagine -- if you go from a 10 µF capacitor to 1 µF, it will take 1/10 the time to charge, so your frequency will go up by a factor of 10. | ||
Verzia zo dňa a času 07:13, 14. október 2010
Časovač 555
The oscilating circuit diagram is pretty simple, featuring the 555, and then a couple of resistors & capacitors that define the actual frequency of the oscillation. Pay attention to the pin numbers.
In reality, when you build it out, the circuit should look like this one:
TODO: image
You can calculate frequency using this formula:
T = 0,693 × (R1 + 2×R2) × C1
C1 is measured in Farads, R1 & R2 are in Ohms, so for values in schematic:
T = 0,693 × ( 100 000 + 2 × 100 000) × 0.000001 = 0,2 seconds (or 4,8 Hz)
If you want a different frequency, you would change the values of C1, R1 & R2. Changing the capicitor is the easiest to imagine -- if you go from a 10 µF capacitor to 1 µF, it will take 1/10 the time to charge, so your frequency will go up by a factor of 10.