A galvanometer G has internal resistance Rg = 10 Ω and full bias current Ig = 0.02A. Now it is refitted into an ammeter with a range of 10A If you want to use 0.03 Ω resistance as shunt resistance, ask: what is the resistance in series for the meter head, and then connect the shunt resistance in parallel?

A galvanometer G has internal resistance Rg = 10 Ω and full bias current Ig = 0.02A. Now it is refitted into an ammeter with a range of 10A If you want to use 0.03 Ω resistance as shunt resistance, ask: what is the resistance in series for the meter head, and then connect the shunt resistance in parallel?

You see, which branch of the galvanometer can only pass the current of 0.02A, and it can be converted into a 10A ammeter
Then the current of the branch where the shunt resistor is located is 10-0.02 = 9.98a
The voltage at both ends of shunt resistor is 9.98 * 0.03 = 0.2994v
Then the resistance of branch where galvanometer G is located is r = 0.2994/0.02 = 14.97
Known RG = 10
Then the resistance of series resistance is RX = r-rg = 14.97-10 = 4.97

The 100 microammeter (the internal resistance of the meter is 2000 Ohm) is refitted into a 50 Ma meter, and the shunt resistance R (s) value in parallel is calculated

Expansion multiple n = 50mA / 100 μ a = 500
R(s)=R(G)/(n-1)=2000/499=4.01(Ω)

There is a sensitive ammeter with an internal resistance of 20 ohm and a measuring range of 15 microampere. Now it is refitted into a 3V voltmeter. What is the resistance in series

0.2 × 10 Λ 6-20 should be

380V power supply length of 650 meters of wire power required for 18 kW, copper wire required for the number of square for specific operation steps

Fast calculation formula of power and current, the relationship between conductor cross-sectional area and current, 2010-04-08 21:23 fast calculation formula of power and current, the relationship between conductor cross-sectional area and current, fast calculation formula of power and current: three-phase motor: 2A / kW, three-phase electric heating equipment: 1.5a/kw, single-phase 220V, 4.5a/kw, single-phase 380V, 2.5A