On 14/07/2016 19:40, Cursitor Doom wrote:
On Thu, 14 Jul 2016 18:40:16 +0100, Lee wrote:

JOOI What version of the 555? If it's a bipolar version they can exhibit
a "crowbar effect", and the 100uf cap is usually suggested to
ameliorate it.

The ones I'm using here are all NE555CN.


It might be interesting to see if you have the same problem with an
ICM7555, but it's much easier just to add the cap, as suggested