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Did I just fry my IC555 ?

by LordVader88
Tags: ic555
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Dec20-12, 08:08 PM
P: 7
Hi, 1st time poster, long time student/hobbiest of math, physics, most sciences. Just getting serious about electronics lately so I made my 1st 555 circuit ever

I made this blinker , it's a short vid with a very simple schematic in it, he draws it as he goes towards the end. I'm using 5V from an old printer PSU, I used 2 series of 2x 4.7kΩ, the circuit only uses "capacitance" in one place.

I had it working fine and I was trying different capacitors and series/parallel caps.

Then I put a 33kΩ between the neg side of the single cap and pin 1 of the 555 (should of had it before the cap to make a little RC series), and it blocked the current almost completely.

So I took it out and now the circuit won't blink anymore. If I place a short where the cap goes (between pin 1 and 2) the LED lights up and says on. But if I use a cap, the LED lights up for the correct amount of time, but never comes back on. Then if I reverse the cap (not ideal I know), the LED will light up for the correct time.

So I can get the LED to light for the right time, but it never comes back on.

The resistors all still measure correctly, so what happened?
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Dec21-12, 07:30 AM
HW Helper
P: 5,475
Replace the IC. If the new one works where the old one wouldn't, I leave you to draw your own conclusions .....
Dec21-12, 08:13 AM
P: 7
only 1 I had, I made another 555 circuit and it doesn't work right either

So I'll have to make some 741 circuits, at least I have a few of them

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