Resistors and Potentiometers Practice Questions — Armed Services Vocational Aptitude Battery (ASVAB)

Question 1Question →

A technician servicing a radio receiver needs to verify a fixed carbon-film resistor with four color bands: Brown, Black, Yellow, and Silver. Calculate the nominal resistance and the minimum allowable resistance under its tolerance rating, and complete the statement below.

Fill in the blanks below

The nominal resistance of the resistor is

\text{k}\Omega

, and its minimum allowable resistance within tolerance is

\text{k}\Omega

.

Show answer & explanation

Answer

The nominal resistance is

100\text{ k}\Omega

and the minimum allowable resistance is

90\text{ k}\Omega

.

According to the electronic color code system, Brown represents 1 and Black represents 0, forming the base number 10. The third band, Yellow, represents a multiplier of

10^4

(

10{}000

), giving a nominal resistance of

10 \times 10{}000 = 100{}000\ \Omega = 100\text{ k}\Omega

. The fourth band, Silver, designates a

\pm 10\%

tolerance. Ten percent of

100\text{ k}\Omega

is

10\text{ k}\Omega

, meaning the minimum allowable resistance under tolerance is

100\text{ k}\Omega - 10\text{ k}\Omega = 90\text{ k}\Omega

(and the maximum is

110\text{ k}\Omega

).

Step-by-Step Solution

1

Decode the significant digits from the first two color bands.

Band 1 (Brown) =

1

, Band 2 (Black) =

0

, giving significant digits

10

.

In standard 4-band EIA color coding, the first two bands represent the first two significant figures of the resistance value.

2

Apply the multiplier from the third color band and convert to kilohms.

Band 3 (Yellow) = multiplier

10^4

(

10{}000

). Nominal resistance

= 10 \times 10{}000 = 100{}000\ \Omega = 100\text{ k}\Omega

.

The third band determines the power of ten by which the significant digits are multiplied.

3

Determine the tolerance percentage from the fourth color band.

Band 4 (Silver) =

\pm 10\%

tolerance.

Silver indicates a manufacturing variation of plus or minus ten percent from nominal value.

4

Calculate the minimum allowable resistance limit.

Tolerance amount

= 100\text{ k}\Omega \times 0.10 = 10\text{ k}\Omega

. Minimum resistance

= 100\text{ k}\Omega - 10\text{ k}\Omega = 90\text{ k}\Omega

.

Subtracting the tolerance deviation from the nominal value establishes the lower acceptable boundary.

Key Concept

Standard 4-band resistor color decoding and tolerance range calculation

Estimated Time:45s

Question 2Question →

A $100\text{ k}\Omega$ linear potentiometer is connected across a $12\text{ V}$ DC power supply, with terminal 1 connected to $+12\text{ V}$ , terminal 3 connected to ground ( $0\text{ V}$ ), and terminal 2 serving as the adjustable wiper. If the wiper is set to $40\%$ of its total travel distance away from terminal 3 toward terminal 1, what is the output voltage measured at terminal 2 relative to ground, and what is the resistance between terminal 1 and terminal 2?

7.2\text{ V}

and

40\text{ k}\Omega

4.8\text{ V}

and

60\text{ k}\Omega

4.8\text{ V}

and

40\text{ k}\Omega

4.8\text{ V}

and

600\ \Omega

Show answer & explanation

Answer: $4.8\text{ V}$ and $60\text{ k}\Omega$

Answer

4.8\text{ V}

output voltage and

60\text{ k}\Omega

resistance between terminal 1 and terminal 2

A linear potentiometer configured across a DC voltage source acts as a continuous voltage divider. With terminal 3 connected to ground (

0\text{ V}

) and the wiper at

40\%

travel from ground, the lower resistance segment

R_{2-3}

is

40\text{ k}\Omega

, yielding an output voltage of

V_{\text{out}} = 12\text{ V} \times (40\text{ k}\Omega / 100\text{ k}\Omega) = 4.8\text{ V}

. The upper resistance segment between terminal 1 (

+12\text{ V}

) and terminal 2 (wiper) is the remaining portion:

100\text{ k}\Omega - 40\text{ k}\Omega = 60\text{ k}\Omega

.

Step-by-Step Solution

1

Calculate the resistance of the lower track section between terminal 2 (wiper) and terminal 3 (ground).

R_{2-3} = 0.40 \times 100\text{ k}\Omega = 40\text{ k}\Omega

The wiper is positioned at

40\%

of total travel measured from the ground terminal.

2

Calculate the output voltage

V_{\text{out}}

at terminal 2 relative to ground using the voltage divider relationship.

V_{\text{out}} = V_{\text{in}} \times \left(\frac{R_{2-3}}{R_{\text{total}}}\right) = 12\text{ V} \times \left(\frac{40\text{ k}\Omega}{100\text{ k}\Omega}\right) = 4.8\text{ V}

A potentiometer connected across a voltage source functions as an adjustable voltage divider.

3

Determine the remaining resistance between terminal 1 (

+12\text{ V}

) and terminal 2 (wiper).

R_{1-2} = R_{\text{total}} - R_{2-3} = 100\text{ k}\Omega - 40\text{ k}\Omega = 60\text{ k}\Omega

The total resistance is divided into two series segments by the wiper contact.

Key Concept

Potentiometer voltage division and wiper segment resistance distribution

Estimated Time:45s

Question 3Question →

A technician is troubleshooting a test circuit connected to a $32\text{V}$ DC power supply. The circuit consists of a fixed resistor $R_1$ in series with a parallel block. The parallel block contains a $12\text{ k}\Omega$ fixed resistor and a variable resistor (rheostat) $R_v$ . The resistor $R_1$ has four color bands: Green, Blue, Red, and Gold. The technician adjusts the rheostat $R_v$ until the total current drawn from the power supply is exactly $4\text{ mA}$ .

What is the resistance setting of the rheostat $R_v$ in kilohms (k $\Omega$ )?

Show answer & explanation

Answer: 3

Answer

3

The total resistance required by the circuit to draw

4\text{ mA}

from a

32\text{V}

source is

8\text{ k}\Omega

. The series resistor

R_1

(Green, Blue, Red) contributes

5.6\text{ k}\Omega

. This leaves exactly

2.4\text{ k}\Omega

required for the parallel section. For a

12\text{ k}\Omega

resistor in parallel with an unknown

R_v

to yield an equivalent resistance of

2.4\text{ k}\Omega

,

R_v

must be set to

3\text{ k}\Omega

.

Step-by-Step Solution

1

Decode the color code of resistor

R_1

.

R_1 = 5.6\text{ k}\Omega

The color bands are Green (5), Blue (6), and Red (multiplier of

10^2

or 100). Thus,

56 \times 100 = 5,600\ \Omega

, which is

5.6\text{ k}\Omega

. The Gold band indicates a 5% tolerance, which applies to real-world variance but does not alter our nominal calculation.

2

Calculate the total equivalent resistance (

R_{eq}

) of the circuit.

R_{eq} = 8\text{ k}\Omega

Using Ohm's Law (

R = \frac{V}{I}

), divide the source voltage (

32\text{V}

) by the total current (

4\text{ mA}

or

0.004\text{ A}

) to find the total resistance required to draw that current.

3

Determine the required equivalent resistance of the parallel block.

R_{parallel} = 2.4\text{ k}\Omega

Since

R_1

is in series with the parallel block, subtract

R_1

from the total circuit resistance to find the resistance of the parallel segment:

8\text{ k}\Omega - 5.6\text{ k}\Omega = 2.4\text{ k}\Omega

.

4

Solve for the rheostat's resistance (

R_v

).

R_v = 3\text{ k}\Omega

The parallel block contains a

12\text{ k}\Omega

resistor and

R_v

. Using the parallel resistance formula

\frac{1}{R_p} = \frac{1}{R_a} + \frac{1}{R_b}

, we get

\frac{1}{2.4} = \frac{1}{12} + \frac{1}{R_v}

. Rearranging gives

\frac{1}{R_v} = \frac{1}{2.4} - \frac{1}{12} = \frac{10}{24} - \frac{2}{24} = \frac{8}{24} = \frac{1}{3}

, meaning

R_v = 3\text{ k}\Omega

.

Key Concept

Integrating Ohm's law with series-parallel equivalent resistance and resistor color code decoding.

Estimated Time:3m 0s

Question 4Question →

Match each resistor configuration or color-coded component on the left with its corresponding electrical characteristic and operating principle on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

The three-terminal potentiometer matches the voltage divider function; the rheostat matches the series current limiter with wiper-to-end protection; the Yellow-Violet-Orange-Gold resistor matches

47\text{ k}\Omega \pm 5\%

; and the Brown-Gray-Green-Silver resistor matches

1.8\text{ M}\Omega \pm 10\%

.

Each item correctly links the component physical description or color code to its precise electrical definition: potentiometers provide variable potential division, rheostats adjust circuit current, Yellow-Violet-Orange-Gold evaluates to

47\text{ k}\Omega \pm 5\%

, and Brown-Gray-Green-Silver evaluates to

1.8\text{ M}\Omega \pm 10\%

.

Step-by-Step Solution

1

Analyze the three-terminal potentiometer and rheostat wiring configurations

A potentiometer connected across a power source acts as a continuous voltage divider (

0\text{ V}

to

V_{\text{in}}

) at the wiper terminal. A rheostat uses a variable two-terminal configuration in series with the load to regulate current.

Variable resistors differ in circuit function based on whether they are wired as three-terminal potential dividers or two-terminal current adjusters.

2

Decode the four-band color code for Yellow-Violet-Orange-Gold

Yellow = 4, Violet = 7, Orange = multiplier

10^3 = 1,000

, Gold =

\pm 5\%

. Value

= 47 \times 1,000\ \Omega = 47\text{ k}\Omega \pm 5\%

.

Standard EIA 4-band color coding assigns significant digits to the first two bands, a decimal multiplier to the third band, and tolerance percentage to the fourth band.

3

Decode the four-band color code for Brown-Gray-Green-Silver

Brown = 1, Gray = 8, Green = multiplier

10^5 = 100,000

, Silver =

\pm 10\%

. Value

= 18 \times 100,000\ \Omega = 1.8\text{ M}\Omega \pm 10\%

.

Standard EIA 4-band color coding converts

1,800,000\ \Omega

using standard metric prefixes to

1.8\text{ M}\Omega

with a silver tolerance of

\pm 10\%

.

Key Concept

Operating principles and terminal configurations of fixed and variable resistors (potentiometers, rheostats, and standard color codes)

Alternative Method

To quickly decode 4-band resistors, write down the two digits (e.g., 47 for Yellow-Violet or 18 for Brown-Gray), append the number of zeros indicated by the multiplier color (3 zeros for Orange = 47,000, 5 zeros for Green = 1,800,000), and simplify to metric units (kilo or mega).

Estimated Time:1m 0s

Question 5Question →

A $10\text{ k}\Omega$ linear potentiometer is wired as a variable rheostat by tying the center wiper (terminal 2) directly to outside terminal 3. If the control shaft is set to $25\%$ of its total travel starting from terminal 1 toward terminal 3, what is the effective resistance measured between terminal 1 and the combined terminal 2/3 connection?

7.5\text{ k}\Omega

2.5\text{ k}\Omega

1.875\text{ k}\Omega

25\text{ k}\Omega

Show answer & explanation

Answer: $2.5\text{ k}\Omega$

Answer

2.5\text{ k}\Omega

A potentiometer wired with its wiper connected to one outer terminal functions as a two-terminal variable resistor (rheostat). Setting the shaft to

25\%

rotation from terminal 1 creates a

2.5\text{ k}\Omega

resistance path between terminal 1 and terminal 2. Because terminal 2 is strapped to terminal 3, the remaining

7.5\text{ k}\Omega

section of the resistive element is completely bypassed by the short, leaving an effective resistance of

2.5\text{ k}\Omega

.

Step-by-Step Solution

1

Determine the resistance of the active resistive track between terminal 1 and the wiper (terminal 2).

R_{1-2} = 0.25 \times 10\text{ k}\Omega = 2.5\text{ k}\Omega

Linear potentiometers divide resistance directly in proportion to shaft travel percentage from the reference end.

2

Analyze the state of the remaining track segment between the wiper (terminal 2) and terminal 3.

R_{2-3} = 7.5\text{ k}\Omega

is short-circuited.

Connecting terminal 2 directly to terminal 3 creates a zero-resistance path across this section, bypassing it entirely.

3

Calculate the total effective resistance between terminal 1 and the joined 2/3 terminal.

R_{\text{eff}} = 2.5\text{ k}\Omega

Current flows through the unshorted

R_{1-2}

segment and exits via the combined wiper/terminal 3 connection.

Key Concept

Rheostat Wiring and Potentiometer Track Division

Estimated Time:45s

Question 6Question →

A quality assurance technician is inspecting a four-band carbon-composition resistor with the color bands in order: Yellow, Violet, Red, and Silver. To meet quality standards, the resistor must operate within its specified manufacturer tolerance. What is the minimum acceptable resistance value, in ohms ( $\Omega$ ), for this component?

Show answer & explanation

Answer: 4230

Answer

The minimum acceptable resistance value is

4230\text{ }\Omega

.

The first two bands (Yellow = 4, Violet = 7) establish the significant figures of 47. The third band (Red) indicates a multiplier of

10^2 = 100

, giving a nominal rating of

4700\text{ }\Omega

. The fourth band (Silver) specifies a

\pm 10\%

tolerance. Subtracting

10\%

of

4700\text{ }\Omega

(

470\text{ }\Omega

) from the nominal rating gives the minimum allowable threshold of

4230\text{ }\Omega

.

Step-by-Step Solution

1

Decode the first two color bands to obtain the significant numerical digits.

Yellow represents the digit

4

, and Violet represents the digit

7

, forming the base value of

47

.

Standard EIA four-band resistor color coding assigns the first two bands as significant figures of the resistance value.

2

Multiply the base significant figures by the power of ten indicated by the third band.

Red indicates a multiplier of

10^2

(

100

), so the nominal resistance is

47 \times 100 = 4700\text{ }\Omega

.

The third band functions as the decimal multiplier for four-band fixed resistors.

3

Identify the tolerance rating from the fourth band.

Silver represents a tolerance of

\pm 10\%

.

The fourth band specifies the allowable deviation range from the nominal resistance value.

4

Calculate the lower allowable resistance threshold.

Tolerance amount is

4700\text{ }\Omega \times 0.10 = 470\text{ }\Omega

. Minimum acceptable value is

4700\text{ }\Omega - 470\text{ }\Omega = 4230\text{ }\Omega

.

The minimum acceptable value represents the nominal value minus the total tolerance deviation.

Key Concept

Four-Band Resistor Color Code Decoding and Tolerance Range Calculation

Alternative Method

Multiply the nominal resistance directly by the minimum percentage factor:

4700\text{ }\Omega \times (1.00 - 0.10) = 4700\text{ }\Omega \times 0.90 = 4230\text{ }\Omega

.

Estimated Time:45s

Question 7Question →

An electronics technician selects a four-band carbon-film resistor with the color sequence Brown, Green, Red, and Gold. What is the nominal resistance and tolerance of this resistor?

150\ \Omega\text{ with } \pm 5\%\text{ tolerance}

1.5\text{ k}\Omega\text{ with } \pm 5\%\text{ tolerance}

1.5\text{ k}\Omega\text{ with } \pm 10\%\text{ tolerance}

15\text{ k}\Omega\text{ with } \pm 5\%\text{ tolerance}

Show answer & explanation

Answer: $1.5\text{ k}\Omega\text{ with } \pm 5\%\text{ tolerance}$

Answer

1.5\text{ k}\Omega\text{ with } \pm 5\%\text{ tolerance}

(

1,500\ \Omega \pm 5\%

)

Decoding the four color bands in standard order gives: Brown = 1 (first digit), Green = 5 (second digit), Red =

10^2

or

\times 100

(multiplier), and Gold =

\pm 5\%

(tolerance). Calculating

15 \times 100\ \Omega

yields

1,500\ \Omega

, which converts to

1.5\text{ k}\Omega

with a

\pm 5\%

tolerance.

Step-by-Step Solution

1

Identify the first two significant digit color bands.

Brown represents the digit 1, and Green represents the digit 5, forming the number 15.

In a standard four-band resistor, the first two bands establish the base significant figures.

2

Determine the multiplier from the third band.

Red represents a multiplier of

10^2

(

100

).

The third band indicates the power of ten by which the significant digits are multiplied.

3

Calculate the nominal resistance value.

15 \times 100 = 1,500\ \Omega = 1.5\text{ k}\Omega

.

Multiplying the base digits by the multiplier yields the total nominal resistance.

4

Identify the tolerance from the fourth band.

Gold indicates a tolerance of

\pm 5\%

.

The fourth band specifies the acceptable manufacturing variation percentage.

Key Concept

Four-band resistor color code decoding and tolerance identification

Estimated Time:35s

Question 8Question →

Match each electronic component or resistor specification on the left with its correct circuit function or definition on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Potentiometer matches with the three-terminal variable resistor used as an adjustable voltage divider; Rheostat matches with the two-terminal variable resistor used to adjust current flow; Fixed Resistor matches with the component providing a single, constant resistance value; Tolerance Band matches with the color-coded marking indicating allowable percentage variation from nominal resistance.

Each item is correctly matched to its standard electrical engineering and ASVAB definition: potentiometers provide variable three-terminal voltage division, rheostats provide two-terminal variable current control, fixed resistors supply a steady ohmic value, and tolerance bands indicate the precision percentage.

Step-by-Step Solution

1

Identify the distinction between the two variable resistor types based on terminal count and primary function.

A potentiometer has 3 terminals and functions as a voltage divider; a rheostat has 2 active terminals in series to regulate current.

Variable resistors differ in wiring configuration: voltage division requires three connections across a potential difference, whereas current regulation requires two inline connections.

2

Identify the definition of a fixed resistor.

A fixed resistor provides a constant, unchangeable ohmic value.

Unlike potentiometers or rheostats, fixed resistors have no moving wiper mechanism.

3

Identify the purpose of the resistor tolerance band.

The tolerance band gives the allowable percentage deviation from the nominal value.

Manufacturing variations mean actual resistance lies within a percentage range defined by the 4th band.

Key Concept

Classification, terminal configurations, and functional specifications of fixed and variable resistors.

Estimated Time:40s

Question 9Question →

A four-band carbon-film resistor has the color bands in the following sequence: Blue, Gray, Brown, and Gold. What is the nominal resistance value and tolerance rating of this resistor?

68\ \Omega\text{ with } \pm 5\%\text{ tolerance}

6.8\text{ k}\Omega\text{ with } \pm 5\%\text{ tolerance}

680\ \Omega\text{ with } \pm 5\%\text{ tolerance}

680\ \Omega\text{ with } \pm 10\%\text{ tolerance}

Show answer & explanation

Answer: $680\ \Omega\text{ with } \pm 5\%\text{ tolerance}$

Answer

680\ \Omega\text{ with } \pm 5\%\text{ tolerance}

Decoding the four color bands in order yields: first band (Blue) = 6, second band (Gray) = 8, third band (Brown) =

\times 10^1

(

10

), and fourth band (Gold) =

\pm 5\%

. Calculating

68 \times 10

gives a nominal resistance of

680\ \Omega

with

\pm 5\%

tolerance.

Step-by-Step Solution

1

Identify the significant digits from the first two color bands

Blue corresponds to the digit 6 and Gray corresponds to the digit 8, forming the significant number 68.

In a standard four-band resistor, the first two bands represent the first and second significant digits of the resistance value.

2

Determine the multiplier from the third color band and calculate the nominal resistance

Brown corresponds to a multiplier of

10^1

(

10

). Multiplying

68 \times 10 = 680\ \Omega

.

The third band indicates the power of ten by which the significant digits are multiplied.

3

Identify the tolerance percentage from the fourth color band

Gold corresponds to a tolerance of

\pm 5\%

.

The fourth band indicates the manufacturing tolerance of the resistor.

Key Concept

Four-band resistor color code decoding

Estimated Time:35s

Question 10Question →

A linear potentiometer has a total resistance of $20\text{ k}\Omega$ between its two outer terminals (Terminal 1 and Terminal 3). If the center wiper (Terminal 2) is adjusted so that the resistance between Terminal 1 and Terminal 2 is $6.5\text{ k}\Omega$ , what is the resistance in kilohms ( $\text{k}\Omega$ ) between Terminal 2 and Terminal 3?

Show answer & explanation

Answer: 13.5

Answer

The resistance between Terminal 2 and Terminal 3 is

13.5\text{ k}\Omega

.

In a three-terminal potentiometer, the resistive element connects between the two outer terminals (1 and 3), providing a fixed total resistance of

20\text{ k}\Omega

. The adjustable wiper (terminal 2) contacts this element and divides it into two series portions such that

R_{1-2} + R_{2-3} = R_{1-3}

. Subtracting the known section (

6.5\text{ k}\Omega

) from the total (

20\text{ k}\Omega

) gives

13.5\text{ k}\Omega

for the remaining section between Terminal 2 and Terminal 3.

Step-by-Step Solution

1

Set up the resistance relationship for the three terminals of a potentiometer.

R_{\text{total}} = R_{1-2} + R_{2-3}

The wiper divides the continuous internal resistive strip into two series sections whose resistances add up to the total end-to-end resistance.

2

Subtract the resistance of the first section from the total end-to-end resistance.

R_{2-3} = 20\text{ k}\Omega - 6.5\text{ k}\Omega = 13.5\text{ k}\Omega

Isolating the unknown segment gives the remaining resistance along the track to the opposite outer terminal.

Key Concept

Potentiometer Terminal Resistance Division

Estimated Time:30s

Question 11Question →

An electronics technician is assembling a circuit that requires a $10\text{ k}\Omega$ fixed resistor. If the first two color bands on the resistor are Brown (1) and Black (0), which color must the third (multiplier) band be?

Red

Orange

Yellow

Brown

Show answer & explanation

Answer: Orange

Answer

Orange

Orange represents a decimal multiplier of

10^3

(

1{}000

). Multiplying the significant digits 10 (from Brown and Black) by

1{}000

yields

10{}000\ \Omega

, which equals

10\text{ k}\Omega

.

Step-by-Step Solution

1

Convert the target resistance from kilohms to ohms.

10\text{ k}\Omega = 10{}000\ \Omega

Standard color code multipliers apply directly to resistance values expressed in ohms.

2

Determine the two-digit base number from the first two color bands.

Brown (1) and Black (0) form the significant digits 10.

In a 4-band resistor, the first two bands represent the leading significant digits.

3

Calculate the necessary multiplier value and identify its corresponding color.

10 \times 10^3 = 10{}000\ \Omega

;

10^3

(

1{}000

) corresponds to Orange.

The third band indicates the power of ten (number of trailing zeros) to multiply by the significant digits.

Key Concept

Four-Band Resistor Color Code Multipliers

Estimated Time:30s

Question 12Question →

Fill in the blanks to complete the statement describing variable resistor terminology.

Fill in the blanks below

A three-terminal variable resistor commonly used to create an adjustable voltage divider is called a , and the internal adjustable contact that moves across the resistive track is called the .

Show answer & explanation

Answer

blank_1: potentiometer; blank_2: wiper

A potentiometer is a three-terminal variable resistor widely used to provide an adjustable voltage division in electronic circuits. The two outer terminals connect across the full resistive element, while the center movable contact, called the wiper, adjusts the output voltage based on its mechanical position.

Step-by-Step Solution

1

Identify the standard three-terminal variable resistor component

A potentiometer (often abbreviated 'pot') is a three-terminal variable resistor configured to divide voltage across its resistive track.

By definition in basic electronics, a three-terminal variable resistor used for voltage division is designated as a potentiometer.

2

Identify the movable mechanical contact mechanism

The sliding contact that traverses the resistive material to tap off a portion of the total resistance is called the wiper.

The standard technical term for the adjustable middle contact of a potentiometer or rheostat is the wiper.

Key Concept

Potentiometer structure and terminology

Estimated Time:30s

Question 13Question →

When inspecting a circuit board, a technician observes a four-band resistor with the color sequence Red, Red, Orange, and Gold. What is the rated resistance value and tolerance of this resistor?

2.2\text{ k}\Omega \pm 5\%

22\text{ k}\Omega \pm 5\%

220\ \Omega \pm 5\%

223\ \Omega \pm 5\%

Show answer & explanation

Answer: $22\text{ k}\Omega \pm 5\%$

Answer

22\text{ k}\Omega \pm 5\%

According to standard electronic color code rules, the first band (Red = 2) and second band (Red = 2) give the two significant digits 22. The third band (Orange =

10^3

) multiplies this base number by

1{}000

, resulting in

22{}000\ \Omega

(

22\text{ k}\Omega

). The fourth band (Gold) indicates a tolerance rating of

\pm 5\%

.

Step-by-Step Solution

1

Determine the first two significant digits from the first and second color bands.

Band 1 (Red) = 2, Band 2 (Red) = 2. Combined digits = 22.

In standard four-band EIA color coding, the first two bands establish the base significant figures.

2

Determine the multiplier from the third band.

Band 3 (Orange) = multiplier of

10^3

(

1{}000

).

Orange corresponds to 3 zeros, or multiplying by

1{}000

.

3

Calculate nominal resistance and append the tolerance from the fourth band.

22 \times 1{}000 = 22{}000\ \Omega = 22\text{ k}\Omega

, with Band 4 (Gold) =

\pm 5\%

.

Combining the base value with the metric prefix gives

22\text{ k}\Omega

with a rated tolerance of

\pm 5\%

.

Key Concept

Four-Band Resistor Color Code Decoding

Estimated Time:35s

Question 14Question →

Four-band resistors use standardized color bands to indicate numerical resistance values. Match each resistor color band with its correct numerical digit value.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Brown matches with digit value of

1

, Orange matches with digit value of

3

, Blue matches with digit value of

6

, and Gray matches with digit value of

8

.

According to the standard EIA resistor color code: Brown represents 1, Orange represents 3, Blue represents 6, and Gray represents 8.

Step-by-Step Solution

1

Recall the standard electronic color code sequence from 0 through 9.

The standardized sequence is Black (0), Brown (1), Red (2), Orange (3), Yellow (4), Green (5), Blue (6), Violet (7), Gray (8), and White (9).

Each color band on a fixed resistor corresponds to an exact base-10 numerical value.

2

Pair each given color band to its corresponding numerical digit.

Brown = 1, Orange = 3, Blue = 6, and Gray = 8.

Direct mapping using the standard EIA color code chart.

Key Concept

Standard Resistor Color Code Digit Values

Estimated Time:35s

Question 15Question →

A four-band carbon resistor displays the color bands Orange, Orange, Brown, and Gold in sequence from left to right. What is the nominal resistance value of this component?

331\ \Omega

33\ \Omega

330\ \Omega

3.3\text{ k}\Omega

Show answer & explanation

Answer: $330\ \Omega$

Answer

330\ \Omega

The first band (Orange) represents the digit 3, the second band (Orange) represents the digit 3, and the third band (Brown) represents a multiplier of

10^1

(10). Multiplying the significant digits by the multiplier yields

33 \times 10 = 330\ \Omega

.

Step-by-Step Solution

1

Decode the first two significant color bands.

Orange corresponds to 3, and the second Orange corresponds to 3, giving the two-digit number 33.

In a 4-band resistor code, the first two bands represent the base significant digits.

2

Determine the multiplier from the third color band.

Brown corresponds to a multiplier of

10^1

(or

10

).

The third band indicates the power of ten by which the significant digits are multiplied.

3

Multiply the significant digits by the multiplier value.

33 \times 10 = 330\ \Omega

.

Combining the base digits and multiplier gives the nominal resistance rating.

Key Concept

Four-Band Resistor Color Code Decoding

Estimated Time:35s

Question 16Question →

An electronic circuit uses a standard four-band resistor with the color bands Yellow, Violet, Brown, and Gold reading from left to right. What is the nominal resistance value of this resistor in ohms ( $\Omega$ )?

Show answer & explanation

Answer: 470

Answer

The nominal resistance value is

470\ \Omega

.

In the standard electronic color code system, Yellow represents 4, Violet represents 7, Brown represents a multiplier of 10 (

10^1

), and Gold indicates a tolerance of

\pm 5\%

. Combining the digits gives 47, and multiplying by 10 produces

470\ \Omega

.

Step-by-Step Solution

1

Decode the first two color bands into the first two digits

Yellow corresponds to 4 and Violet corresponds to 7, giving the base number 47

The first two bands on a four-band resistor represent the first and second significant figures of the resistance value

2

Decode the third band into the decimal multiplier

Brown corresponds to a multiplier of

10^1

(

10

)

The third band indicates the power of ten by which the base number must be multiplied

3

Calculate the total nominal resistance

47 \times 10 = 470\ \Omega

Multiplying the base digits by the multiplier gives the rated nominal resistance in ohms

Key Concept

Four-band resistor color code decoding

Estimated Time:30s

Question 17Question →

A technician tests a four-band carbon resistor marked with the color sequence Green, Blue, Red, and Gold from left to right. What is the rated resistance and tolerance of this resistor?

562\ \Omega \pm 5\%

5.6\text{ k}\Omega \pm 10\%

5.6\text{ k}\Omega \pm 5\%

560\ \Omega \pm 5\%

Show answer & explanation

Answer: $5.6\text{ k}\Omega \pm 5\%$

Answer

5.6\text{ k}\Omega \pm 5\%

(

5,600\ \Omega \pm 5\%

)

According to the standard EIA four-band color code, Green represents the digit 5, Blue represents the digit 6, Red indicates a multiplier of

10^2

(

100

), and Gold represents a tolerance of

\pm 5\%

. Combining these values yields

56 \times 100 = 5,600\ \Omega

(

5.6\text{ k}\Omega

) with a tolerance of

\pm 5\%

.

Step-by-Step Solution

1

Determine the first and second significant digits from the first two color bands.

Green corresponds to 5 and Blue corresponds to 6, giving the significant digits 56.

In standard four-band EIA color coding, the first two bands represent the first two significant figures.

2

Determine the multiplier from the third color band and calculate nominal resistance.

Red indicates a multiplier of

10^2

(

100

). Multiplying

56 \times 100 = 5,600\ \Omega = 5.6\text{ k}\Omega

.

The third band determines the power of ten by which the significant digits are multiplied.

3

Determine the tolerance percentage from the fourth color band.

Gold indicates a tolerance of

\pm 5\%

.

The fourth band specifies the manufacturing tolerance rating of the component.

Key Concept

Four-band resistor color code decoding

Estimated Time:35s

Question 18Question →

When examining fixed through-hole resistors, what electrical property is directly governed by the component's physical dimensions, and what unit is used to express this capability? Complete the technical statement below.

Fill in the blanks below

Although the printed color bands on a standard carbon-composition resistor indicate its electrical resistance and tolerance, the physical size of the resistor body determines its rating, which is measured in .

Show answer & explanation

Answer

power (or wattage) and watts (W)

In electronic components, the physical package size of an axial-lead fixed resistor determines its ability to radiate heat into the surrounding air. Consequently, larger resistors have higher power (wattage) ratings, which are quantified in watts (W). The actual resistance value in ohms and the manufacturing tolerance percentage are represented by the color-coded bands printed on the component body.

Step-by-Step Solution

1

Identify the electrical property determined by a resistor's physical dimensions and surface area.

Power rating (or wattage / power dissipation capacity)

A larger physical package provides more surface area to safely dissipate thermal energy generated by current flow without overheating or damaging the component.

2

Identify the standard unit of measurement for electrical power dissipation.

Watts (W)

Resistor power ratings are specified in watts, with common standard through-hole ratings including

1/8\text{ W}

,

1/4\text{ W}

,

1/2\text{ W}

,

1\text{ W}

, and

2\text{ W}

.

Key Concept

Resistor physical package size correlates directly to power dissipation rating in watts rather than resistance value in ohms.

Estimated Time:45s

Question 19Question →

During a quality control inspection, a technician measures a resistor marked with the color bands Brown, Gray, Red, and Gold. For this resistor to meet its manufactured specification, what is the acceptable range of measured resistance?

171\ \Omega\text{ to } 189\ \Omega

1,710\ \Omega\text{ to } 1,890\ \Omega

1,620\ \Omega\text{ to } 1,980\ \Omega

172.9\ \Omega\text{ to } 191.1\ \Omega

Show answer & explanation

Answer: $1,710\ \Omega\text{ to } 1,890\ \Omega$

Answer

1,710\ \Omega\text{ to } 1,890\ \Omega

A four-band resistor with colors Brown (1), Gray (8), Red (

10^2 = 100

), and Gold (

\pm 5\%

) has a nominal value of

1,800\ \Omega

. With a

\pm 5\%

tolerance, the allowable variance is

1,800 \times 0.05 = 90\ \Omega

. Subtracting and adding

90\ \Omega

gives the acceptable operational range of

1,710\ \Omega

to

1,890\ \Omega

.

Step-by-Step Solution

1

Determine the nominal resistance from the first three color bands.

Brown = 1, Gray = 8, Red = multiplier of

10^2

(

100

). The nominal value is

18 \times 100 = 1,800\ \Omega

.

In a standard four-band resistor, the first two bands represent significant digits and the third band represents the power-of-ten multiplier.

2

Identify the tolerance percentage from the fourth band.

Gold band =

\pm 5\%

.

The fourth band specifies the manufacturing tolerance rating.

3

Calculate the acceptable tolerance deviation in ohms.

1,800\ \Omega \times 0.05 = 90\ \Omega

.

The allowable deviation is found by multiplying the nominal resistance by the tolerance percentage.

4

Calculate the minimum and maximum acceptable resistance boundaries.

Minimum:

1,800 - 90 = 1,710\ \Omega

; Maximum:

1,800 + 90 = 1,890\ \Omega

.

The acceptable range spans from nominal minus tolerance to nominal plus tolerance.

Key Concept

Decoding four-band resistor color codes and calculating nominal tolerance boundaries

Estimated Time:45s

Question 20Question →

Electronic circuits utilize various fixed and variable resistive components to control voltage, limit current, and calibrate operating points. Match each resistor type on the left with its primary functional description or application on the right. Which pairs correctly match each component to its function?

Click a left item, then click its matching right item

Show answer & explanation

Answer

Potentiometer matches the three-terminal voltage divider description; Rheostat matches the two-terminal series current regulator description; Trimmer Resistor matches the miniature calibration component description; Wirewound Resistor matches the high-power coiled-wire construction description.

Each component is mapped directly according to its terminal count, internal construction, and operational role: Potentiometers are three-terminal voltage dividers; Rheostats are two-terminal series current controllers; Trimmers (trimpots) are compact PCB calibration resistors; Wirewound resistors are heavy-duty components constructed with wire coils around a ceramic core for high-power dissipation.

Step-by-Step Solution

1

Differentiate between three-terminal and two-terminal variable resistor operations.

Identify the potentiometer as the three-terminal voltage divider and the rheostat as the two-terminal current limiter.

Potentiometers divide voltage across three terminals, whereas rheostats vary resistance in series using two active terminals.

2

Identify the distinct mechanical and physical packaging of precision alignment components versus power components.

Match the trimmer resistor (trimpot) to calibration/alignment and the wirewound resistor to high-power ceramic-core construction.

Trimpots are miniature preset controls adjusted during calibration, while wirewound resistors are constructed to handle significant thermal dissipation.

Key Concept

Classification, terminal configuration, and circuit applications of fixed and variable resistors.

Estimated Time:1m 0s

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