Using a switch to bypass 555 timer?

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sjaguar13

New Member

• Jun 29, 2003

• #1

I have LEDs that blink using a 555 timer. I want them to be able to stay on. How would I use a switch to do this? Would I need a SPST switch?

 

A

afs87

New Member

• Jul 1, 2003

• #2

Please Specify

Hello,

When you say 'stay on' do you mean you want them to stay on after the first flash? If so I would recomend wireing the 555 as a monostable and connecting an inverter and thyristor to the output. You could have a switch on the tyristor if you want to turn the latching on or off (a standard on-off off-on latching spst should do). If not please explain.

afs87

 

S

sjaguar13

New Member

• Jul 2, 2003

• #3

I want to be able to make them flash, then flick a switch and they are no longer flashing.

 

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bryan

Member

• Jul 2, 2003

• #4

Why not add a on/off switch to the power supply?? Or do you mean stop flashing but still stay on

 

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sjaguar13

New Member

• Jul 2, 2003

• #5

Yeah, I want it to stay on, but just not flash.

 

P

pebe

Member

• Jul 3, 2003

• #6

One way is to wire the 555 as an astable, with threshold and trigger wired together. From their junction, connect the timing cap to ground and the timing resistor to output.

To make the output stay high, switch the th/tr junction to ground - to make it stay low, switch the junction to +ve rail.