"Jim Thompson" wrote in
message ...
On Sat, 14 May 2011 15:13:16 -0400, Spehro Pefhany
wrote:

On Fri, 13 May 2011 14:43:34 +0100, the renowned "Ian Field"
wrote:


"John Fields" wrote in message
...
On Thu, 12 May 2011 21:59:28 +0100, "Ian Field"
wrote:


"Jim Thompson"
wrote
in
message ...

How do you post to SED ?:-)

Infrequently.

---
Practice makes perfect.


Panic over - I replaced the 555 with a Signetics part, it still runs
pretty
warm but is within safe limits without the clip on heatsink.

The one I took out was branded ST.


What was the entire part number? NE555? SA555? SE555? or TS555?



Best regards,
Spehro Pefhany

There's only a few ways to make a 555 run hot...

VDD higher than spec.

Huge capacitive (or resistive) load on the output

Mis-connecting "Discharge"

Clearly Ian, like lots of posters here, won't post their schematic for
fear of criticism... yet no-schematic is the guaranteed way to get
criticized ;-)


The circuit is so simple the criticism is best deserved by those who can't
understand the description I gave.