Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.




434 posts

Ultimate Geek
+1 received by user: 12
Inactive user


Topic # 112888 25-Dec-2012 23:31
Send private message

I have a dmm which says on the back .. this meter must not be connected to high energy sources which have transient voltages greater than 1000v. This includes 240v mains supply. 

What does that mean, how does it work explain it? 
I can understand if the meter cannot handle over 1000 volts but ..
a) What would happen if i connected it to more than 1000 volts 
b) Why does that include 240 volts mains supply ? or do they just say that to protect people who don't really know what they are doing


Create new topic
1216 posts

Uber Geek
+1 received by user: 142


  Reply # 737257 26-Dec-2012 02:41
Send private message

Answers: 
  a) Anything from nothing, to KABLAM and take off your fingers.
  b) Probably it's just C-Y-A, the 240v mains line could technically have a massive spike, but you'd hope not.

Edumacational material for you from the king of Multimeter teardowns, reviews and rants, Dave Jones:
http://www.youtube.com/watch?v=M-FZP1U2dkM#t=6m13s (blowing up meters with 4kv)

http://www.youtube.com/watch?v=Ewyf9mzIfi0#t=55s (Dave ranting about a meter that blew up on 240v)

http://www.youtube.com/watch?v=zUhnGp5vh60 (all about Input Protection)





---
James Sleeman
I sell lots of stuff for electronic enthusiasts...


1462 posts

Uber Geek
+1 received by user: 269

Subscriber

  Reply # 737280 26-Dec-2012 09:11
Send private message

because the insulation on the test leads and multimeter is only rated to 1000V above that and you start getting leakage voltage which will give you and electric shock

 
 
 
 


124 posts

Master Geek
+1 received by user: 6


  Reply # 737376 26-Dec-2012 14:55
Send private message

It appears the multimeter does not have sufficient protection to safely break high fault currents (such encountered with the AC mains), this means in worst case scenario, when internal protection device such as a fuse opens, there is risk of arcing, fire, and harm to user. If you plan on regularly using a multimeter, and going anywhere near the AC mains with it, buy a quality brand such as Fluke, they are expensive, but last almost forever. And, use the maker's own leads that came with it.
Otherwise, just keep the cheapie strictly for low voltage measurements.

gzt

9165 posts

Uber Geek
+1 received by user: 1291


  Reply # 737380 26-Dec-2012 15:17
Send private message

I bought a $20 cheapie a while back. Quality of the leads and probes absolutely awful. Measurement accuracy varies wildly depending on battery voltage and multiple other factors.

Decent ones start from round $100 at jaycar. Fluke are great but expensive for a general purpose model.



434 posts

Ultimate Geek
+1 received by user: 12
Inactive user


  Reply # 737414 26-Dec-2012 17:10
Send private message

cool thanks, i understand it now

Create new topic



Twitter »

Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

New Zealand government to create digital advisory group
Posted 16-Dec-2017 08:47


Australia datum changes means whole country moving 1.8 metres north-east
Posted 16-Dec-2017 08:39


UAV Traffic Management Trial launching today in New Zealand
Posted 12-Dec-2017 16:06


UFB connections pass 460,000
Posted 11-Dec-2017 11:26


The Warehouse Group to adopt IBM Cloud to support digital transformation
Posted 11-Dec-2017 11:22


Dimension Data peeks into digital business 2018
Posted 11-Dec-2017 10:55


2018 Cyber Security Predictions
Posted 7-Dec-2017 14:55


Global Govtech Accelerator to drive public sector innovation in Wellington
Posted 7-Dec-2017 11:21


Stuff Pix media strategy a new direction
Posted 7-Dec-2017 09:37


Digital transformation is dead
Posted 7-Dec-2017 09:31


Fake news and cyber security
Posted 7-Dec-2017 09:27


Dimension Data New Zealand strengthens cybersecurity practice
Posted 5-Dec-2017 20:27


Epson NZ launches new Expression Premium Photo range
Posted 5-Dec-2017 20:26


Eventbrite and Twickets launch integration partnership in Australia and New Zealand
Posted 5-Dec-2017 20:23


New Fujifilm macro lens lands in New Zealand
Posted 5-Dec-2017 20:16



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.