| Electronics > Projects, Designs, and Technical Stuff |
| Small, Cheap AC Panel meters - Review and teardown |
| (1/1) |
| intabits:
I did a quick and dirty review and teardown of these cheap digital AC panel meters that read voltage and current. I got a blue one and a green one:- The insides (I can't see any markings on the main chip):- Pros:- Bright clear display Cheap (abut US$3.60) Easy to mount Can sense up to 100A (and up to 500V) Cons:- Doesn't show currents less than about 750mA Current readings seem to be be low/inaccurate Voltage readings are also a little hit and miss, only accurate to within about 2-3%. For low currents they are probably pretty useless, but if the load is always over 1 amp, they may have a place. I'm thinking that it may be possible to add a trimpot to calibrate the current measurement. (But I need to get something to accurately compare it against) Video:- |
| magic:
Is this for mains? How much overvoltage before :-BROKE ;D |
| intabits:
Yes, it is for mains. The box says: 50V to 500V, and 0-100A (meter seems to need a minimum of about 20V to operate) |
| SiliconWizard:
How is the current sensing achieved? |
| intabits:
The unit comes with a current transformer, that connects via a 2 pin inline connector to a flying lead coming out of the back of the device. The mains is connected via 2 screw terminals on the body of the unit. I should have included a pic showing all this:- |
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