This is a timer circuit using a 555 chip.
Uses of Capacitors
Capacitors take a certain amount of time to charge and discharge. They are therefore used in circuits where something happens after a certain time.
| A capacitor charges of discharges and when the voltage across it reaches
a certain value this triggers something to happen. This is a timer circuit using a 555 chip. |
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Capacitors store energy. There are situations where a burst of energy is needed.
| This is the flash on a camera. A capacitor charges from a
battery then discharges very quickly through a bulb producing a very bright
flash. The defibrillation paddles on the title page for this unit are another example. |
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Because capacitors take time to charge and discharge they act a bit like resistors in a.c. circuits.
| Capacitors will "resist" a.c. but there resistance (actually called
reactance) depends on the frequency of the a.c. signal.
They are used in circuits called High Pass Filters as they have a lower resistance to higher frequencies. |
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