Hi, I'm not big into electronics, just wondering if anyone can tell me how this circuit would function. Thanks in advance.
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The LED would flash on and then slowly fade over a period of around 100 seconds.the LED would flash on and then go off
Thank you Les, I'm trying to design a very simple circuit to sound a buzzer and light an LED if my freezer door is left open by accident. Hence the values of capacitor and setting of the potentiometer.When the last connection was made connecting up the circuit the LED would flash on and then go off. The length of the flash would depend on the value of the capacitor and resistor. This assumes that the capacitor was initially in a discharged state. With a perfect capacitor pressing the normally closed push button would have no effect. With a real capacitor which had some leakage then after holding the switch pressed for some time the LED would flash on when it was released. The time the push button needed to be held pressed for the LED to flash when it was released would depend on the type of capacitor. The time that the button needed to be held pressed would be from several minutes to many months.
Les.
Thanks AlbertThe LED would flash on and then slowly fade over a period of around 100 seconds.
The LED would come on immediately the switch is closed and then slowly fade out.So approximately after 100 seconds the LED would flash on and then go off. Is there a modification that would make it stay on till the switch was opened again? Maybe need a relay and a separate circuit for the LED / buzzer output?
Thanks for your response Albert.The LED would come on immediately the switch is closed and then slowly fade out.
If you want the LED to stay on until the switch is opened remove the capacitor from the circuit.
Aw this is perfect, thank youThis circuit would do that:
View attachment 192260
If R2 was a variable resistor could I adjust the time delay?Aw this is perfect, thank you
Yes.If R2 was a variable resistor could I adjust the time delay?