simonsez
Well-known member
What kind of circuit that can boost current? I have a mA meter (1000mA) and want to make it capable reading a few ma for my project,. may be some kind of VU buffer? Thank you for your help..
Current booster?
- Thread starter simonsez
- Start date
Help Support GroupDIY Audio Forum:
there often is a current shunt resistor somewhere, that can be removed?
simonsez
Well-known member
Should i open the meter?gyraf said:
Mark Burnley
Well-known member
1000mA is 1 Amp, so you'd need a pretty hefty booster circuit!
As Jakob mentions, this meter will be a much lower sensitivity movement with a shunt (probably a small loop of resistance wire for 1A FS) connected across the input terminals, usually internally.
Be very careful opening moving coil meters- there are two gotchas- one is to make sure that there are absolutely no small magnetic particles on your bench (steel filings, chips of metal etc) -sweep your bench with an old speaker magnet first (if the bits get into the gap between the magnet and the moving coil it's a nightmare to repair) and secondly, the "zero adjust" peg has to be located carefully into the small gap in the adjuster arm when you put it back together.
Usuall, the front removes leaving the meter face attached to the rear panel/connections. Usually 3 small screws hold this front cover on (located around the perimeter at the base)
To access the current shunt, you usually remove the scale- this is held on by two v. small screws (often hidden from view when front panel is in place)
Proceed with caution!!
(a magnifier lamp is handy- and don't touch the needle pointer!)
Mark
As Jakob mentions, this meter will be a much lower sensitivity movement with a shunt (probably a small loop of resistance wire for 1A FS) connected across the input terminals, usually internally.
Be very careful opening moving coil meters- there are two gotchas- one is to make sure that there are absolutely no small magnetic particles on your bench (steel filings, chips of metal etc) -sweep your bench with an old speaker magnet first (if the bits get into the gap between the magnet and the moving coil it's a nightmare to repair) and secondly, the "zero adjust" peg has to be located carefully into the small gap in the adjuster arm when you put it back together.
Usuall, the front removes leaving the meter face attached to the rear panel/connections. Usually 3 small screws hold this front cover on (located around the perimeter at the base)
To access the current shunt, you usually remove the scale- this is held on by two v. small screws (often hidden from view when front panel is in place)
Proceed with caution!!
(a magnifier lamp is handy- and don't touch the needle pointer!)
Mark
simonsez
Well-known member
Ok thank' s Mark, I will look inside with care...Thank you
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