# Momentary switch

#### Berzin

Joined Dec 17, 2020
59
Hello guys well today I want your help as I am trying to light a led with two different circuits on it of 12 volts dc with the help of 12 volt relay so it would a type of some momentary switch

#### KeithWalker

Joined Jul 10, 2017
1,780
Can you give us a little more information. Then maybe we can offer some suggestions.
What are the two different circuits?
What will the relay do?
What sequence of events do you want to happen when you close the momentary switch and then open it?

#### Berzin

Joined Dec 17, 2020
59
Both circuit consist of a BC547 a resistor 220 ohm and ends with led so i want that the circuit no 1 starts and lights the led with the help of a relay and when the circuit no 2 starts it' should trigger the led and stop the circuit no 1 and both the circuits release the positive point for the led

#### KeithWalker

Joined Jul 10, 2017
1,780
Defining every step of the sequence of a circuit is the first part of the design. Without that, we can not proceed.
Does circuit No.1 start when the power is applied?
What starts circuit No.2?
How long must LED No.2 stay on for?

#### Berzin

Joined Dec 17, 2020
59
Defining every step of the sequence of a circuit is the first part of the design. Without that, we can not proceed.
Does circuit No.1 start when the power is applied?
What starts circuit No.2?
How long must LED No.2 stay on for?
Both the circuit are a part of Parerall power lines and hence both are start by the power

#### KeithWalker

Joined Jul 10, 2017
1,780
If both circuits start as soon as the power is connected, I still have no idea what you want to happen.
All you have told me so far is that there are two transistors driving two LEDs.
When the power is applied, the LEDs turn on.
When LED N0.2 turns on they both turn off.
That doesn't make much sense to me, and there is a relay in there somewhere but I don't know what it does.
Please supply a step by step description of the sequence of what the LEDs and relay are supposed to do.

Last edited: