Combination Circuits

If a resistor in a parallel circuit has twice the resistance of a second resistor, it will have __?__ the current of the second resistor.

1/2

In a combination circuit, the amount of current that passes through each resistor is exactly the same. (True/False)

False

Is it necessary to know the current through a series circuit in order to calculate the voltage drop across the resistors in the circuit using the laws of proportionality?

No

The total Voltage dropped across a series-parallel circuit equals __?__.

The Supply Voltage

The first step is to reduce the combination circuit to a simpler circuit one part at a time. (True/False)

True

A circuit in which some of the components are series connected, while other components are parallel connected, is called a(n) __?___ or ___?___ circuit.

combination series-parallel

In a combination circuit, the current leaving the source is (the same as/different than) the current returning to the source.

the same as

When determining if components in a circuit are in series or parallel with each other, you should ___?___ the current ___?___ path(s).

trace current

In a series circuit the __?__ is directly proportional to the resistance, while in a parallel circuit the ___?____ is inversely proportional to the resistance.

voltage current

If resistor "B" of a series circuit has three times more resistance than resistor "A", then the voltage across resistor "A" will be __?__ (1/3/3 times) the voltage across resistor "B".

1/3

What are the basic steps in reducing a combination circuit to its simplest form?

1. Reduce one part of the circuit at a time. 2. Redraw the circuit, exchanging the equivalent circuit for the original resistors, this helps you visualize the next required steps. 3. Ensure that all series resistors have been combined before a parallel portion is reduced. 4. Combine parallel portions to a single resistor. 5. Repeat the combining equivalent resistors until all portions are reduced to one equivalent resistance.

In a three-wire, single phase system, the line-to-line voltage is ___?___ -volts and the line-to-neutral voltage is __?__ -volts.

240 120

What is the first step necessary to to allow calculation of voltages in a combination circuit containing resistive loads in series and parallel?

Calculate the equivalent resistance

In combination circuits, after solving for the total current through the circuit, the values for the ____?____ through the individual resistors maybe calculated by working backwards from the total equivalent ___?____ using Ohm's law.

Current Resistance

Write the Law of Proportionality in equation form. (Assume only two resistors in the circuit).

Er=Et x ( Rr/Rt)

Write the expression for finding the current through resistor R1 of a parallel circuit containing two resistors when the total circuit current and the resistance of the resistors are known.

Ix = It x Rt/Rx

Branch-circuit currents are generally calculated by applying ___?____ to the voltage across the branch and the branch resistance.

Ohm's law

The NEC requires that the continuity of the grounded conductor (neutral) in multiwire branch circuits not be terminated directly on the receptacle. instead a pig tail must be taken to the receptacle so that the continuity of the grounded conductor does not depend on the device. In light of what you have just learned, explain the purpose of this Code rule.

To reduce the possibility of a neutral being opened.

For combination circuits, trace the current paths through the circuit to determine which resistors are connected in series and which are connected in parallel. (True/False)

True

No matter how complex a combination circuit is, it can be reduced to a single voltage , current, and resistance. (True/False)

True

Three resistors in parallel can be reduced to a single equivalent resistor. (True/False)

True

In series circuits, when the current through the circuit and the resistance of each component is known, you can easily calculate the ___?___ for each component in that circuit using Ohm's law.

Voltage Drop

In parallel circuits, when the voltage applied to the branch and the branch resistance is known, can easily calculate the ___?____ for that branch.

current

In a series circuit, the voltage across any load is __?__ (directly\inversely) proportional to the value of the resistance of that load.

directly

When simplifying resistance in series and parallel , a(n) ___?___ resistancce is substituted back into the circuit that represents the total value as all of the resistances that were combined.

equivalent

In a parallel circuit, the current through any resistor is ___?___ proportional to the value of that resistor.

inversley

It ___?___ (is/is not) necessary to know the voltage in a parallel circuit to figure current using the Law of Proportionality.

is not

How much current flows in the neutral in a balanced three-wire system?

none

In reducing series-parallel circuits to the simplest form, the equivalent circuit is usually represented by ____?___ that is connected in ___?___ with the voltage source.

one equivalent resistance series

Any circuit in which the current is split or follows two (or more) alternative paths is called a(n) ___?___ circuit.

parallel

When it is difficult to recognize which parts of a circuit are series connected and which are parallel connected in a combination circuit , it is often necessary to ___?____ the circuit.

redraw

Give three reasons why three-wire, single-phase systems are used.

reduces instillation costs reduces line loss reduces voltage drop provides 240 volt circuit

In a parallel portion of a series-parallel circuit, the voltage across a parallel branch can be found by taking the total branch current times the __?__ of the parallel branch.

resistance

In a three-wire system, how large should the neutral wire be when compared to the hot wires? Why?

same size

Any circuit in which the same current flows through all components is a(n) __?___ circuit.

series

The sum of all of the voltage drop across the resistors in a series circuit is equal to the __?__ source voltage.

source

In a series circuit or parallel circuit, the total power consumed by the circuit is equal to Et times __?__, or the __?__ of the power consumed by each resistor

sum total

The neutral of an unbalanced three-wire system is opened. What happens to the voltage on the line with the smallest load?

the circuit becomes a 240 v series circuit line with a smaller load has a higher resistance more than half the voltage across it, voltage rises about 120 volts