HNC project - analogue meters

[Vitalspark]

Hi, I am in year 2 of my HNC electrical and electronic engineering, I have been issued the task to create an analogue multimeter capable of testing AC and DC voltages.

Carrying out my research for the past couple of weeks into the construction of these old analogue multimeters there is very limited information via websites/textbooks and even through request at the local instrumentation company.

Do any of you guys have any decent info on analogue meters or have researched in this before!

Any help and advice is greatly appreciated thanks!

 

[sheephat]

What a task!

AC voltmeters and ammeters : Ac Metering Circuits - AC
Make your own multimeter : Dc Circuits - DC

Had a brief read, id assume the only way to change the AC/DC is with a rocker switch of some sort.

Did you draw the short straw?

 

[Vitalspark]

Thanks I had used the DC template you supplied also but my rheostat resistors didn't work out to a 50V DC scale, so I suppose back to the calcs to make sense of it somewhere, I reckon il have to use some sort of bridging rectifier for it - it does sound difficult but can't be that bad otherwise how would we be testing electrical circuits I want to focus my course towards instrumentation seeing as its the most important part of a sparks toolkit. Has to be complete by December though haha a tight deadline!

 

[sheephat]

Small Transformer to up the voltage?

Most vt systems will up or down the voltage it detects to make it scale correctly, in theory you need to generate a signal where 0 is your lowest value (0v) and 1 is your highest value (100v) for example, everything inbetween is scaled so 0.5v on your meter circuit is 50v in real life, as long as the back plate is correct you should nail it.

Hope they help sounds interesting what your trying to accomplish

 

[Marvo]

Are you looking at using discreet components like shunt resistors or can you use op-amp or in-amp?

http://www.ahmetozkurt.net/MEC515/week7_electrical.pdf

 

[Vitalspark]

Are you looking at using discreet components like shunt resistors or can you use op-amp or in-amp?

http://www.ahmetozkurt.net/MEC515/week7_electrical.pdf

I am looking at using shunt resistors I tried connecting a 30k resistor in parallel with a 30k potentiometer all in series with a 15k resistor formulas don't make sense on ecad Isis bloody nightmare!!

 

[Vitalspark]

Are you looking at using discreet components like shunt resistors or can you use op-amp or in-amp?

http://www.ahmetozkurt.net/MEC515/week7_electrical.pdf

Just seen your link this is ace cheers! Really good stuff to review!!

 

[Paultrim123321]

Wow, brings back memories, good look with the project, reminds me of my PowerPoint presentation in front of 25 fellow students and lecturers for my project.

 

[GlennT]

Has anybody here completed their Engineering Science Assessments?