A 150 kOhm resistor has a nominal resistance of 150,000 ohms. In a standard four-band resistor color code, the first three bands are brown, green, and yellow:
\(\displaystyle 15 \times 10{,}000 = 150{,}000\ \Omega\)
This resistance value is commonly used where a circuit needs relatively low current, such as a voltage-divider leg, transistor bias network, high-impedance sensor input, timing circuit, pull-up or pull-down network, or feedback path. The nominal value alone is not the complete design value: the tolerance band establishes the minimum and maximum resistance the installed component may have.
Use the Resistor Color Code Calculator to decode the observed bands and confirm the resistance value before checking circuit behavior.
Four-Band Color Code Calculation
A four-band resistor uses:
| Band | Function | 150 kOhm Color |
|---|---|---|
| First band | First significant digit | Brown = 1 |
| Second band | Second significant digit | Green = 5 |
| Third band | Multiplier | Yellow = (10^4) |
| Fourth band | Tolerance | Depends on the resistor |
The first two bands form the number 15. Yellow applies a multiplier of (10{,}000).
\(\displaystyle 15 \times 10^4 = 150{,}000\ \Omega\)
The same value can be written as:
\(\displaystyle 150{,}000\ \Omega = 150\ \text{k}\Omega = 0.15\ \text{M}\Omega\)
When identifying a physical resistor, read the tolerance band from the opposite end. The tolerance band is often spaced slightly farther from the other bands, which helps establish the reading direction.
Tolerance Range
The tolerance band defines the permitted manufacturing variation around the nominal 150 kOhm value. Calculate the resistance limits as:
\(\displaystyle R_{\text{minimum}} = R_{\text{nominal}} \times (1 - \text{tolerance})\)
\(\displaystyle R_{\text{maximum}} = R_{\text{nominal}} \times (1 + \text{tolerance})\)
For a 150 kOhm resistor, the calculator starts with the nominal value of 150,000 ohms and applies the selected tolerance percentage.
| Tolerance | Minimum Resistance | Maximum Resistance |
|---|---|---|
| ±1% | 148,500 Ω | 151,500 Ω |
| ±5% | 142,500 Ω | 157,500 Ω |
| ±10% | 135,000 Ω | 165,000 Ω |
A resistor marked brown-green-yellow-gold, for example, is a 150 kOhm ±5% resistor. Its actual measured resistance may fall anywhere from 142.5 kOhm to 157.5 kOhm at the applicable reference conditions.
Calculation Example
Enter the observed four color bands in the Resistor Color Code Calculator:
1. Select brown for the first significant digit: 1.
2. Select green for the second significant digit: 5.
3. Select yellow for the multiplier: (10{,}000).
4. Select the observed tolerance-band color.
The decoded nominal resistance is:
\(\displaystyle 15 \times 10{,}000 = 150{,}000\ \Omega\)
For a gold tolerance band:
\(\displaystyle 150{,}000 \times (1 - 0.05) = 142{,}500\ \Omega\)
\(\displaystyle 150{,}000 \times (1 + 0.05) = 157{,}500\ \Omega\)
The final result is 150 kOhm ±5%, with a possible range of 142.5 kOhm to 157.5 kOhm.
Circuit Use and Voltage Review
A 150 kOhm resistor may be suitable in a high-resistance voltage divider, but the actual divider output changes with the resistor tolerance and the tolerance of the matching resistor.
For a two-resistor divider:
\(\displaystyle V_{\text{out}} = V_{\text{in}} \times \frac{R_2}{R_1 + R_2}\)
Use the Voltage Divider Calculator to evaluate the nominal output voltage, then test the resistor tolerance limits when the output feeds a threshold-sensitive input, analog-to-digital converter, comparator, gate, or control circuit.
A 150 kOhm resistor can also limit current in circuits with a known applied voltage. Use the Ohm’s Law Calculator to calculate current, voltage, or power:
\(\displaystyle I = \frac{V}{R}\)
For example, at 24 V across a 150 kOhm resistor:
\(\displaystyle I = \frac{24}{150{,}000} = 0.00016\ \text{A}\)
\(\displaystyle I = 0.16\ \text{mA}\)
The nominal resistor dissipation is:
\(\displaystyle P = \frac{V^2}{R} = \frac{24^2}{150{,}000} = 0.00384\ \text{W}\)
That is approximately 3.84 mW under nominal conditions. Confirm the resistor’s actual power rating and applied voltage rating rather than selecting a component from resistance alone.
Field Verification
Verify the actual resistor with a meter when the circuit is sensitive to tolerance, failure diagnosis, or replacement-component identification. Isolate or lift one lead when practical because parallel circuit paths can produce a lower resistance reading than the component’s true value.
The color-code calculation identifies nominal resistance and tolerance. Component selection and field acceptance also require verification of:
- Resistor wattage and allowable continuous dissipation
- Maximum working voltage and transient voltage exposure
- Insulation system and temperature rating
- Precision, stability, and temperature coefficient requirements
- Circuit loading, especially in voltage-divider and high-impedance input applications
- Whether the resistor is in a branch circuit control circuit, electronic assembly, or other application with separate equipment and installation requirements