Newnes Circuit Calculations Pocket Book

28 Circuit calculations pocket book

Example 4 There is a flow of 20 x 10

3

C in a resistor over a period

of 1 hour. Calculate the current.

Q 20 x 10

3

/ = — = = 5.56 A

t 1 x 60 x 60

10 PRINT "PROG 29"

20 PRINT "THIS PROGRAM COMPUTES CURRENT"

30 INPUT "ENTER CHARGE IN COULOMBS" ; Q

40 INPUT "ENTER TIME IN SECONDS*' ; T

50 LET I=Q/T

60 PRINT "CURRENT = " I "AMPS"

3.3

Ohm's law

The current flowing in a conductor is proportional to the applied

voltage. If the applied voltage is V (volts) and the resulting current

is / (amperes), the relationship between V and / is

V

I = —

R

where R is the conductor resistance in ohms. This is known as

Ohm's law.