Im thinking, why all current meters use shunt resistor and not hall effekt sensor ?
By the way, that is the difference.
If you should build a current meter that can measure up to 1 A dc, what would you use ?
Hi and thanks for reply.johnf wrote:Hi, siqu.
A current meter has to offer a very low resistance to the rest of the system, and the low resistance shunt connection is traditional, cheap and effective.
The small voltage drop across the shunt resistor, which could be a massive bar of metal ( for large currents) provides a linear signal which can be sensed and amplified if necessary.
A Hall effect element could either a) sense the magnetic field around the power cable,
or b) be configured to carry the current, or a fraction of it , and a permanent magnet be applied so as to produce a Hall voltage.
Where AC power is concerned, current transformers , with insulated coils and ferrite cores , are in widespread use.
An important design consideration is, whether there is a need to have isolation between the measuring circuit and the operating circuit. This might rule out the simple shunted meter option.