I like the video. Could you please explain NTC in more depth. I want to use one as a soft starter for my variac. How do i choose the right one? What are all these numbers on an NTC?
NTC stands for negative temperature coefficient. In other words, the resistance decreases as temperature increases. Looking at the graph in the video (around 3:00), this should be obvious. What may not be obvious is the near-logarithmic change is resistance. Note that the vertical scale is changing by factors of ten. Thus, you need to think of this in terms of the resistance changing by a certain factor over a range of temperature versus changing by so-many ohms. For example, there is roughly a ten fold change in resistance as temperature is increased by 50 degrees (from 25C to 75C). The plot is not perfectly straight, and the change is a little faster at lower temps and a little slower at higher temps. The trick here is to design the circuit around the performance of the available sensor (as shown with simplified examples later in the video). Ultimately, it's up to you to determine the environmental variation you need to cover, and design the circuit to match that.
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I like the video.
Could you please explain NTC in more depth.
I want to use one as a soft starter for my variac. How do i choose the right one? What are all these numbers on an NTC?
NTC stands for negative temperature coefficient. In other words, the resistance decreases as temperature increases. Looking at the graph in the video (around 3:00), this should be obvious. What may not be obvious is the near-logarithmic change is resistance. Note that the vertical scale is changing by factors of ten. Thus, you need to think of this in terms of the resistance changing by a certain factor over a range of temperature versus changing by so-many ohms. For example, there is roughly a ten fold change in resistance as temperature is increased by 50 degrees (from 25C to 75C). The plot is not perfectly straight, and the change is a little faster at lower temps and a little slower at higher temps.
The trick here is to design the circuit around the performance of the available sensor (as shown with simplified examples later in the video). Ultimately, it's up to you to determine the environmental variation you need to cover, and design the circuit to match that.