WARNING: 30V was a mistake — better to keep voltage down 12V as a beginner! I tested it over a very short time. Got the things hot over a long time with much less voltage — apparently not enough energy was dissipated to destroy the components.
Thermistors are a type of resistors, according to Wikipedia. Two thermistors black-white (18p written on it) and gold-orange-gold-yellow (no text). If the colour coding is the same to resistors and reading up-to-bottom, the former is 8 Ohms and the last one is 4k Ohms. I tested both with 30V: the former warm, the last not warm, the current 0,0A (not measurable with my equipment).
Sizes are 0.2cm times 0.3cm for both of the components.
Accepted Power Estimate by size(tip): 3.14*(0.025m)^2 = 0.00196... so P ~=10^-3
- How to estimate current as it was below
10^-2? - How to read thermistors' colour coding and what does 18p mean, 18 pico Ohms or some change?
Best Answer
Thermistors are only a type of resistor in a limited sense. Within a given temp. range they behave linearly in current. The packaging of Thermistors varies quite a lot, Glass beads to plastic packs. As far as I know there is no color coding that is common. I did a check on Omega and Honeywell's site. No mention of a color coding there either. I would think the 18p is a manufacturing code and not an electrical spec.
Also, testing with 30V!! How big are these things!