[Amps] SB220 Meter blown

[Adrian]

The shunt resistor is across the meter to set the working range of 
application for the FSD corresponding to the full range of measurement.

, that's why it is called a shunt resistor. The protection diodes are in 
parallel, and so is the meter.

https://www.youtube.com/watch?v=Q-CE-ZbBuTQ

Your statement is technically incorrect.

Maximum Forward Voltage Drop per element at 1.0A DC -*1.1*V Once it 
shorts VD falls closer to zero.


On 18/5/20 6:59 pm, Steve Thompson wrote:
> Rich was talking about putting diodes across the current measuring 
> resistor, not directly across the meter itself. Typically the resistor 
> generates something in the region of 0.5-2V which the meter reads via 
> a series resistor.
>
> Most moving coil movements need less than 10mA and less than 0.2V to 
> go to full scale. A meter which reads higher current without external 
> resistors will almost certainly have an internal shunt. If you're 
> trying to protect a meter with an internal shunt you probably need to 
> look at the biggest Shottky diodes you can afford as they conduct at  
> lower voltages than silicon ones.
>
> At 20+A glitch current, the voltage across a 1N5400 type diode will be 
> in the order of 1.5-2V.
>
> Steve G8GSQ
>