Testing Resistors In My Lab

Resistors seem like a simple topic. Just Ohm’s Law:

and a digital volt meter that reads resistor values in Ohms.

But different resistors by size, value, tolerance, temperature compensation, age, and manufacture have a problem with noise. I present several resistor types all with the same value of 100kΩ. Each resistor is tested for stability over time and temperature.

Use this simple procedure to test your own resistors before use in projects that require low noise such as scientific instrument prototypes. I start with 4 minutes of resistance data logging at room temperature followed by an additional 3 minutes of resistance data logging at an elevated temperature using my pinched fingers around the body of the resistor.

Fluke 125B Resistance Data Log / Part	Increase Temperature during Resistance Data Log / Part Using Heat from Finger

Test results for 8 different 100KΩ resistors in my lab. Resistors 2), 7), and 8) appear to be the worst after heat applied.

Resistor Info	Photo	7 Minute Resistance Plot
1) 100kΩ 1% Metal Film 1/4 Watt. Purchased on Amazon: 1280 Pieces 64 Values Resistor Kit, 1% Assorted Resistors 1 Ohm-10M Ohm 1/4W Metal Film Resistors – Brand: Aniann
2) 100kΩ 1% Metal Film 1 Watt. Purchased on Amazon: 1000pcs 1W Resistor Kit, 1 Ohm – 1M Ohm 1 Watt Metal Film Resistor Assortment Kit with 1%. Brand: AUKENIEN
3) 100kΩ 1% Metal Film 1/4 Watt, 50ppm. 31 Values, 100 pcs per Value Resistor Kit. Purchased on Newark. Brand: Farnell
4) 100kΩ 1% Metal Film 1/4 Watt, from my parts bin.
5) 100kΩ 10% Carbon 1/2 Watt, from my parts bin.
6) 100kΩ 5% Carbon 1 Watt, from my parts bin.
7) 100kΩ 5% Carbon 1/4 Watt, from my parts bin.
8) 100kΩ 5% Carbon 1/2 Watt, from my parts bin.

In this last test I verify the stability of my resistance data logging test procedure. Use this information if you would like to repeat this test on your own resistors.

Baseline Resistance Test	Baseline Resistance Test Results	Test Voltage Used During Resistance Tests	Test Voltage

References