2 - Electrical Measurements

Total Resistance in a series circuit is equal to...?

the sum of individual resistances. Rt = R1 + R2 + R3

How do you find total resistance in a parallel circuit?

1/Rt = 1/R1 + 1/R2 + 1/R3

What is the symbol for current?

I

What is the formula for current in a parallel circuit?

I1 + I2 + I

What is resistance measured in?

Ohms

How many paths for current in a series circuit?

One path

What is the symbol for resistance?

R

How are resistance measurements taken?

Resistance measurements are taken in parallel (across) a component with the power off, and disconnected at least one side from the circuit.

Current measurements in a parallel circuit will be the same/different at different places in the circuit?

Same

Describe a series circuit

Series circuits have one path for current. Voltages are additive. Resistance is additive

If current increases in a circuit, and voltage remains the same, what happens to the resistance? A. Increases B. Decreases C. Stays the same D. None of these

B. Decreases

Voltageis the amount of ______________________ ______________________ in a circuit.

Electrical Pressure

True or False - In parallel circuits, voltages are different on each branch

False - The voltages are the same in each branch

When using a voltmeter, where do you attach the red lead?

To the highest potential point

When using voltmeter, where do you attach the black lead?

To the lowest potential point

In a(n) __________ circuit, the voltage available to each branch is equal to the source voltage. A. parallel B. series C. short D. open

A - Parallel

What is the unit of measurement for current?

Ampere

How do you measure continuity with a DMM?

Apply test leads across a conductor. A beep will let you know if there is continuity

Current in a series circuit __________. A. is different through each component in the circuit B. is the same through each component in the circuit C. is the sum of all the individual currents. D. none of these

B - is the same through each component in the circuit

A known reference point in an electrical circuit is called a __________. A. common B. Zero Reference C. negative D. positive

B. Zero Reference

Current in a(n) __________ circuit is divided among the branches of the circuit. A. series B. parallel C. open D. short

B. parallel

A __________ circuit is one in which there is only one path for current to travel. A. complex B. series C. parallel D. closed

B. series

Two resistors are placed in series. One has a resistance of 500 Ω. The other has a resistance of 100 Ω. What statement is NOT true? A. they will have the same current level flowing through them B. the 500 Ω resistor will have a smaller voltage drop than the 100 Ω resistor because voltage and resistance are inversely proportional. C. They will provide a total of 600 Ω of resistance. D. the 500 Ω resistor will have a larger voltage drop than the 100 Ω resistor.

B. the 500 Ω resistor will have a smaller voltage drop than the 100 Ω resistor because voltage and resistance are inversely proportional. *** Feedback: B. the 500 Ω resistor will have a smaller voltage drop than the 100 Ω resistor because voltage and resistance are inversely proportional.

The potential difference between two points in a circuit is called __________. A. current B. voltage C. resistance D. None of the above

B. voltage

If a wire has continuity, it __________. A. cannot conduct current B. will have almost no resistance C. cannot be used in a circuit D. has an open

B. will have almost no resistance

Which of the following statements is not true about measuring the resistance of a component that is connected in a circuit? A. Turn off the power supply. B. Disconnect one of the component leads from the circuit. C. Make sure the power supply is on. D. Connect the leads across the component.

C. Make sure the power supply is on.

Resistance is measured in units of __________. A. Volts B. Watts C. Ohms D. Amps

C. Ohms

To measure current through a component, the multimeter must be connected __________ the component. A. across B. in parallel with C. in series with D. without

C. in series with

The amount of voltage that is used on each load in a circuit depends upon the __________ of each load. A. drop B. continuity C. resistance D. amps

C. resistance

What is current?

Current is the amount of electrons flowing through a circuit, or in other words, movement of electrons.

When loads are connected in series, their individual resistances are __________. A. multiplied B. divided C. subtracted D. added

D - Added

When loads are connected in series, their individual voltages are __________. A. multiplied B. divided C. subtracted D. added

D - Added

Placing your multimeter across a component (in parallel) would indicate a __________. A. current measurement B. resistance measurement C. voltage measurement D. both B & C

D - B & C

D. DPDT double break

D. DPDT double breakWhat type of switch is used in the circuit below? A. SPST single break B. SPDT double break C. DPST single break

A multimeter is a multipurpose device that can measure __________. A. only voltage B. only current C. only resistance D. voltage, current, and resistance

D. voltage, current, and resistance

What is a voltmeter?

It is a device that measures the voltage between two points in an electrical circuit.

What is a multimeter?

It is a multipurpose device that can measure voltage, current, and resistance.

What does a voltmeter do?

It measures the voltage between two points on an electrical circuit

Current measurements in a series circuit will be the same/different at different places in the circuit?

It will be the same

What does continuity tell you?

It will only tell you if there is a complete path

Voltage measurements are taken in series/parallel?

Measurements are taken in parallel

how do you calculate resistance in a series circuit

The total resistance of a series circuit is equal to the sum of individual resistances. Rt = R1 + R2 + R3

What do all voltage drops in a series circuit add up to?

They add up to the voltage coming out of the battery

How are current measurements taken?

They are taken in series with the component.

Why should measurements be measured from the lowest voltage range?

To improve accuracy

In Series Circuits what does... I Lamp = I Resistor = I Coil = Total current =

Total Current

In Series Circuits, what does .... R Lamp + R Resistor + R Coil =

Total resistance

True or False - In parallel circuits there are more than one path for current

True

True or False - Resistance total is LESS than the smallest branch.

True

What is Voltage measured in? What is the symbol?

Volts V or E

V R1 = 10V V R2 = 10V V R3 = 10V Total Voltage = 10V

What is V R1, V R2, V R3 and total voltage?

12

With your multimeter connected as shown in the diagram (black lead to ground), what would your meter read at point 1__________?

0

With your multimeter connected as shown in the diagram(black lead to ground), what would your meter read at point 4_________?

Voltage in a parallel circuit is the same/different on each branch?

is the same as the voltage gain

What is resistance?

opposition to current flow

Voltage measurements are always taken in _______________________ (across) a component.

parallel