water temperature sensor resistance

Most sensors we supply use NTC thermistors—negative temperature coefficient—meaning resistance drops as temperature rises. The relationship follows a nonlinear curve, often fitted by the Steinhart-Hart equation. For instance, a 10kΩ at 25°C thermistor may drop to about 3kΩ at 50°C and rise above 30kΩ near 0°C. The exact curve depends on material formulation and is provided with each calibration.

It depends on your data logger’s excitation current and the length of your cable. A 10kΩ base resistance works well for many short-cable applications because it balances self-heating and resolution. Longer cables may benefit from 100kΩ or higher to reduce lead resistance effects. We can help match the resistance to your logger’s input range to avoid saturation or poor signal-to-noise ratio.

Yes. While 10kΩ and 100kΩ at 25°C are common, we can build thermistors with non-standard base resistances (e.g., 2.2kΩ, 30kΩ) and even tailor the R-T curve for a specific temperature span if your project requires tighter resolution in a narrow band.

We use glass-encapsulated or epoxy-sealed NTC chips that resist moisture ingress. The materials are selected for low ionic contamination, which is the main cause of drift. Every sensor goes through a thermal cycling burn-in before final calibration, effectively aging the element so that field resistance readings remain within published drift specs—typically less than 0.02°C per year for well-manufactured thermistors.

Our standard probes output raw resistance, which you connect to a temperature logger configured for the specific R-T curve. If your system expects a 4–20mA signal or Modbus output, we can integrate a compact transmitter inside the probe housing so you get an industry-standard conditioned signal without separate electronics.