Difference between revisions of "Backup LED Light"
From ScienceZero
(New page: Tiny automatic light powered by a backup capacitor This circuit will light the LED when the supply voltage is removed. In normal operation the base of the transistor is grounded and no cu...) |
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Tiny automatic light powered by a backup capacitor | Tiny automatic light powered by a backup capacitor | ||
| − | This circuit will light the LED when the supply voltage is removed. In normal operation the base of the transistor is grounded and no current will flow through the LED. When the supply voltage is removed the diode will isolate the base from the negative on the capacitor and the 10K pull-up resistor will make sure the transistor is conducting. | + | This circuit will light the [[Light emitting diode|LED]] when the supply voltage is removed. In normal operation the base of the transistor is grounded and no current will flow through the LED. When the supply voltage is removed the diode will isolate the base from the negative on the capacitor and the 10K pull-up resistor will make sure the transistor is conducting. |
The capacitor is 1F, 5.5V. | The capacitor is 1F, 5.5V. | ||
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| + | [[image:Backuplightschematics.gif]] | ||
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[[Category:Electronics]] | [[Category:Electronics]] | ||
Latest revision as of 22:11, 1 February 2007
Tiny automatic light powered by a backup capacitor
This circuit will light the LED when the supply voltage is removed. In normal operation the base of the transistor is grounded and no current will flow through the LED. When the supply voltage is removed the diode will isolate the base from the negative on the capacitor and the 10K pull-up resistor will make sure the transistor is conducting. The capacitor is 1F, 5.5V.
