The World Of Radio Meters

 

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Amp meters have very low resistance, and need to be put into the circuit to get a reading.

If the amp and voltmeters were inversed, the amp meter because of its low resistance would be a dead short across the battery.

The voltmeter because of its high resistance would stop the circuit from working. 

 

R1 + R2

 

R1  =  43Ω

R2  = 270Ω

Total Resistance = 313 Ω

 

 

 

The reading on the amp meters should be

.0383amp or 38..3 mA
 

I       X        R

 

V
 
Isosceles Triangle: Oval: A Low R Oval: V High R

 
 

 
 

 
 

 
 

                                                     R2
 

 
 

 
 

 
 

 
 

R1
 

12V
 

 
 
Oval: AVolt meters have very high resistance, and need to be external to get a reading.