How can a 555 timer be damaged

[thecritic]

I had a working 555 timer monostable circuit. But I accidentally supplied the + and - reversed for a moment. Is this likely to damage the IC. Also what are other ways to damage it?

 

[HarveyH42]

They are pretty tough chips, can't remember destroying any. Haven't worked with the CMOS version, might be a little more sensitive. I'm sure they fry, but never tried.

 

[Pommie]

Also what are other ways to damage it?

Hit it with a big hammer.

HTH

Mike.

 

[Hero999]

Reversing the supply voltage might be enough to destroy and IC or at least make it unreliable.

 

[audioguru]

A supply voltage that is too high will destroy all ICs.
If an IC drives an inductor then the IC is destroyed by the very high flyback voltage produced when it turns off power to the inductor.
If you short the output of a 555 then its very high output current will fry it.

 

[antknee]

They are so cheap it would be easier to replace it than worry about whether it is damaged, assuming you have a spare.

 

[Hero999]

Agreed, throw it away, even if you think it might be all right. Don't risk building a project with the faulty IC and waste time troubleshooting.

 

[thecritic]

I think its already damaged beyond use

Contrary to what some of you people think, the IC is not just unreliable but totally damaged. The output is constantly high no matter what. Also, the IC goes on getting hot towards a point your hand will burn touching it. Only misbehave I did was to reverse the supply voltage (12 V) for a moment. Also, I don't think Its such a cheap IC here, A pair costs about 30 Rs, Comparable to what a average lunch costs. What I mean is I can't just throw it away if I suspect it, I need to confirm it.

 

[Boncuk]

Contrary to what some of you people think, the IC is not just unreliable but totally damaged. The output is constantly high no matter what. Also, the IC goes on getting hot towards a point your hand will burn touching it. Only misbehave I did was to reverse the supply voltage (12 V) for a moment. Also, I don't think Its such a cheap IC here, A pair costs about 30 Rs, Comparable to what a average lunch costs. What I mean is I can't just throw it away if I suspect it, I need to confirm it.

If you carefully remove the plastic case you might probably see the indian smoke signals escaping from it.

 

[thecritic]

If you carefully remove the plastic case you might probably see the indian smoke signals escaping from it.

I didn't get you, Could you kindly be more clear and formal ??? Only thing I disagree with you guys is that I just don't find it logical to throw away a chip simply because you suspect if might be damaged or unreliable. Isn't there some accepted things that are sure to damage the IC and some things that are sure to not damage. What I need to confirm is Should every time I accidentally reverse the polarity I should throw away the IC or that I can do that after some confirmation.

 

[audioguru]

We can buy about 20 555 ICs here ($.50 each) for the average cost of a lunch ($10.00) in a restaurant here.
Our average income ($60,000 per year) can buy 16 average lunches per day.
So one 555 IC costs almost nothing.
Reversing the polarity of an IC's power supply probably destroys it immediately.

 

[tytower]

If you can catch the smoke you might be able to get it back in.
Whats a R Rand , Rouble ,Rhial Razoo ?

 

[Boncuk]

If you can catch the smoke you might be able to get it back in.
Whats a R Rand , Rouble ,Rhial Razoo ?

You didn't read the entire abbreviation. It says "Rs". I guess it's Rupies (currency of India)

 

[Boncuk]

I didn't get you, Could you kindly be more clear and formal ??? Only thing I disagree with you guys is that I just don't find it logical to throw away a chip simply because you suspect if might be damaged or unreliable. Isn't there some accepted things that are sure to damage the IC and some things that are sure to not damage. What I need to confirm is Should every time I accidentally reverse the polarity I should throw away the IC or that I can do that after some confirmation.

It is obvious and very clear: An IC connected to the supply source reversely burns up immediately, no matter how long it is connected.

Connect a protection diode (or two) in front of your circuit for the power supply.

Use a Schottky diode (for least voltage drop) rated for the current of your circuit.

P.S. I didn't mean the population of India, but red Indians living in America.

 

[thecritic]

I don't know weather you meant that or not but I felt (after reading some of the posts) being laughed at for not being able to afford to buy plenty of those ICs.
And one thing, Rupees is not just the currency of India but also of some other countries whose citizens don't like to be called Indians.

 

[audioguru]

I did not laugh at you.
I pointed out that the standard of living and costs of things in your part of the world are completely different in my part of the world.

Aren't you in India? You did not fill in your location so we don't know that you are not in India but you are maybe in Sri Lanka, Burma or Nepal.

 

[Hero999]

I thought RS meant RadioShack?

Anyway, try shopping around, it sounds like you're being ripped off, try looking on eBay there's lots of cheap stuff on there.

 

[JimB]

Contrary to what some of you people think, the IC is not just unreliable but totally damaged.
The output is constantly high no matter what.
Also, the IC goes on getting hot towards a point your hand will burn touching it.

In that case it is broken, cut the legs off and throw it in the bin.

Only misbehave I did was to reverse the supply voltage (12 V) for a moment. Also, I don't think Its such a cheap IC here, A pair costs about 30 Rs, Comparable to what a average lunch costs.

Another thing which will damage ICs is static electricity.
When I am working on a circuit board I wear an anti-static wrist strap which is earthed.
Why? because of painfull expensive experience, having damaged a couple of expensive modem ICs (about £11 each) my wife never let me live it down!

What I mean is I can't just throw it away if I suspect it, I need to confirm it.

I think you just did confirm it.

The output is constantly high no matter what.
Also, the IC goes on getting hot towards a point your hand will burn touching it.

If 555s are so expensive, you need to be more carefull when working with them, maybe build reverse voltage protection into your circuit.

In this situation, my signature says it all.

JimB

 

[antknee]

In that case it is broken, cut the legs off and throw it in the bin.

Why cut the legs off?

Antknee.

 

[antknee]

To "The critic",

Provide a location and probably someone will provide you with a local source of $1 or equivalent 555 timers.

Antknee.