answer 2 questions

[wsfsdetkrsyt]

does anyone know how do do i Draw a circuit that will convert a galvanometer with a full-scale deflection (f.s.d.) of 1mA and internal resistance of 20Ω into an instrument capable of measuring up to 1A.

and another circuit to convert the same galvanometer to read 10 volts f.s.d.

thanks

 

[James]

https://docs.rs-online.com/a79e/A700000006690527.pdf

 

[telectrix]

so you want 1mA through the meter, so to measure 1A fsd, you need 999mA through a parallel shunt. your meter is 20 ohms, use ohms law to determine the value of your shunt resistance, but due to the tolerances of resistors, you'll never get accuracy.

 

[Avo Mk8]

First part - parallel resistor (eg 0.02 ohm)
second part - series resistor (eg 10k ohm, well 9.98k ohm to be exact)
(assuming I've got my sums right!)