Milli ammeters

[AnnNos]

5 burnt out milli ammeters in 2 days. Is it possible to replace the fuse wire? Has anyone repaired burnt out units successfully. Does anyone have an ammeter - milli or micro - that has a proper fuse inside that can be replaced or do you just buy new meters?

Help

[DavidPeterson]

gave up on ammeters and just use multimeters - it's easier to replace fuse

[AnnNos]

Y8 are doing an electrical skills task and reading the meter is one of the skills.

[Labbie]

Our repair chap does ours.

[smiley]

Interestingly, if the kids go anywhere with electrical skills these days, they'll only be using digital meters anyway! That's just a comment on the course, by the way.

We're even finding less use for the good old thermometer these days. There's just so much more one can do with a digital unit, without the risk of breakage.

[bunsen]

You can repair but a little fiddly, you become quicker with practice. Here's a link to the WA tech site which has repair guides.
http://www.rtg.wa.edu.au/repairs/meters/meters.htm

I repair mine a little different, when soldering in the replacement reistance wire you will have to adjust its length to meet required resistance.
To do this, after soldering in the piece of resistance wire I connect damaged meter in a circuit with a known working meter,if repaired meter is not reading the same than you will need to adjust length of wire. Process may need to be repeated a few times until readings are the same. (will require soldering, checking, unsoldering, adjusting, re soldering and re checkng)

Make sense, hope so.
Cheers
Dave

[AnnNos]

Thanks for your help

I've done some repairs and it does take some repeating. I'll see if I can talk them into using multimeters from now on.

Regards
Ann

[bunsen]

No matter how many times you explain the importance of connecting an ammeter in series, someone will always do it wrong. Because it doesn’t go bang or erupt in a ball of smoke teachers do not realise how frustrating it is to repair these things. My latest attempts to reduce repairs was to take photos of all circuit setups with labels, these images are stored with the relevant subjects and are easily available to all teachers via the network. It does make life easier for teachers (and me) if they remember them, as they can project the image onto the big screen and every can see if the circuit is connected correctly before flicking the switch. As a further reminder I include a laminated photo of the image (with its locations details on the network) with the prac setup. Took a little time to do but a lot less then repair time. I’ve included an example