Circuit with delay

319

12:12:47

The current gain of the transistor can be used to extend the discharge time of the capacitor. The circuit has a 100nF electrolytic capacitor which serves as a storage capacity. It charges quickly when you press a PUSH button and when the key is released the capacitor supplies current to the base of the transistor. The LED will light up and dim slowly. High resistance base resistor gives a time constant of about 10 seconds. After that interval, the base current is not strong enough to excite the transistor for complete conductivity.

published 6 years ago

Molar

6 years ago

Neat circuit. 👍

fatcat2

6 years ago

With contact resistances of 70m ohms, the transient doesn't change much according to the current gain.

Robert_Kidd

6 years ago

You have a 100nF capacitor but text refers to 100mF capacitor.

PrathikP

6 years ago

http://everycircuit.com/circuit/6633789407887360

PrathikP

6 years ago

Here you go, I've optimised you circuit. And remember, whenever you simulate such circuits, you must do so in real time, i.e., at 1s/s.

TuXAPuK

6 years ago

Can be cool upgraded with and gate... Where both inputs are linked

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