Electrical Circuit Calculations Series Circuits
fraudMany circuits have more than one conversion device in them
(i.e. toaster. heater. lamps etc.) and some have more than one source of electrical energy.
If the circuit components are connected end to end to form a single loop it is a ries-circuit
Remember that current is the rate at which electrons move through the circuit. So as in veral hos
connected in ries to form one long line, water can only come out at the far end at the same rate that it enters at (neglecting friction).
Each component has a volt drop across it (and is the force required to convert the electrical energy to some other form). All of the volt drops in a circuit add up to f. (Voltage) of the supply.
In the above circuit E = V1 + V2
(This assumes that the connecting wires have very little resistance, which is not an unreasonable
assumption to make.)
Ammeters
Ammeters are instruments that measure current and so have to be in the current path, that is, in ries with the device who current is being measured.
The volt drop across each component can be calculated using Ohms law if the circuit current and the value of each component's resistance is known.
(Remember that f of the supply is across the whole circuit and not just across anyone of the components.)
Worked Example:
研究生美国留学费用
• If the circuit shown draws
10 amps from the supply,
lawlessstlcalculate the volt drop across
each resistor and the volume
of the f.
超级回路Note that as it is a ries circuit
the current is the same in all resistors.
V1 = IR1 = 10 x 10 = 100V
V2 = IR2 = 10 x 20 = 200V
V3 = IR3 = 10 x 5 = 50V
As the volt drops all add up to the supply voltage E
E = V1 +V2 +V3
= 100+200+50
= 350v
If the supply voltage but not the
current volume had been given
in the above circuit we could
have calculated it becau the
total resistance of a ries
circuit R total is simply the sum
of the resistances
This is the total resistance across
the supply so this circuit can
be replaced by a single resistor
of 35 ohms.
The supply current I = E/R t
= 350/35
= 10 amps
Look at the circuit below. Even though we have connected two resistors you should be able to state immediately what the volt drop across the two resistors together is.
The voltage drop is, of cour, 24 volts.
If the f E and the parate resistances are given, calculate the circuit current and the volt drops across each resistor.
1 Add the resistances to give the total resistance
2 Calculate the circuit current by dividing the supply E by R T
3 Calculate the volt drop across each resistor by using the formula:
V1 =I x R1
V2 =I x R2
V3 =I x R3 etc.
A Worked Example
• Given the circuit below calculate
I The total resistance
2 The current.
3 The volt drop across each resistor-
1. Total resistance: R total=R1 + R2 + R3
= 40 + 5 + 80
minimum是什么意思
ohms =125
2. Current (I) is found by using Ohms Law: I = E/R T
= 250/125
Therefore, circuit current I = 2amps
(3) Volt drop across each resistor:
Volt drop across R1: V1= I x R1
40
= 2
x
volts
=80
Volt drop across R2: V2= I x R2
5
x
= 2
volts
=10
Volt drop across R3: V3= I x R3
80
x
绿日乐队
= 2
volts
=160
As a check, the volt drops across the resistors should add up to the supply voltage.
眼线笔怎么用i.e = VD1 + VD2 +VD3
=80+10 + 160
= 250 volts.
Parallel Circuit当然可以的英文
When each of a number of circuit components is connected across the same supply or between the
same two points in a circuit, they are said to be connected in parallel.
Whenever resistors are in parallel there is the same volt drop across each one. In figure one the volt drop across R1, R2 and R3 will be the same and will be the supply voltage. In figure two the volt drop across E2, R3 and R4 will be the same and it will be V2
小学英语教学总结Unlike the ries connection the current in resistors in parallel is not the same (unless they are the same value of resistance).
