Wednesday, 6 June 2018

Beware fake multi-meter leads

I bought these multi-meter leads on eBay for £2.99. They are advertised as "16PCS/Set Multimeter Probe Pin Test Leads Cable Multifunction Digital Clip Kit". I was attracted to them by the large number of accessories including pin type plugs that fit old analogue multi-meters.

When they arrived I discovered that the wires are steel and have a resistance of about 1 Ohm each, which makes them about as useful as a chocolate teapot. Any resistance measurement gets 2 Ohms added . Current measurements on the amps range drop large voltages, the wires get hot and would burn if left on for more that a few seconds.

Voltage measurements would be accurate enough but where the attachments screw on there is exposed metal, so not suitable for high voltages.

I got a full refund and get a set of these instead for £2.97.

They claim to be CE cat III rated for 1000V and 20A. Their resistance is only 64 milliohms. Not bad but my UNI-T UT61E came with 600V 10A rated ones that measure 44 milliohms and my EEVblog BM235 wins with 24 milliohms for 1000V 10A probes.

I got them to replace these old ones that belong to a multi-meter I inherited from my Dad. They have numerous burns from touching a soldering iron.

I dug out this old meter when I realised all my modern digital meters only go up to 1000V at most. This one goes up to 6KV!

I think it was purchased sometime in the early 1970s. It is branded Honor Model TE-12, made in Japan. I have seen identical ones on the web branded Lafayette. I don't think you would get away with connectors like that for 6KV nowadays!

Saturday, 2 June 2018

Avoiding annoying Blogger cookie warnings

Being warned by every web site that it uses cookies is very annoying. I don't see how it is useful because virtually every site uses cookies.

When looking at a Blog hosted by Blogger it is even more annoying because it warns for every new page of a blog visited. Looking at the cookie it uses to decide whether to warn about using cookies I noticed it stores the path of the page relative to the blog. That is why it warns for each page of someones blog. However it looks like it won't warn for sub paths of the path in the cookie. So if you visit the root of the blog and dismiss the warning there it gets rid of the warnings for every other page in the same blog. This is a lot more reasonable and probably the way it should work by default.

It is also annoying that this will expire in a year. If every website I visit repeats the warning every year it will continue to be a constant stream of warnings forever.