A thermocouple circuit produces an amplified voltage difference of 0.5V when there is a change in temperature of 10°C.Thermocouple amplified voltage at 30°C is 2.5V.The thermocouple circuit is to be used as a temperature sensor to maintain an oven temperature between 40°C and 80°C by switching ON and OFF the power supply to the oven.The oven is to be controlled by schmitt trigger in connection with the thermocouple circuit.The schmitt trigger is to be connected to ±15V. (a) Determine schmitt trigger voltage levels (upper and lower trigger level) (b)Sketch hysteresis loop and show all necessary voltage levels (c)draw the schmitttrigger circuit and determine reference voltage
your thermocouple output is not linear, at 10C its 0.5v, yet at 30C its 2.5v, it should be 1.5v at 30C?
It's not ok. If it is nonlinear, then knowing what the voltage is at 10C and 30C is not enough information for us to determine what it is at 40C and 80C. It's also not ok since you haven't shown any effort to solve it yourself. Show what you have done thus far and where you are having problems and we will help guide you back to the right path. And, please, don't just say that you don't know were to start.
IMHO, the english is not good enough to base interpretation on which specific words were used. I took "change" to mean a difference between the sense point and the reference point. But if that isn't what it means, what is the "change" relative to? And what is the 30C referring to?
I see it as a data point (2.5V@30°) and a slope (0.5V/10°). (We do have to assume a sign for the slope, which was an omission by the instructor.) From this we can deduce: V=0.05*T + 1 From this equation you can find the voltages at 40° and at 80°. Design a Schmitt trigger with these threshold voltages.
I'm pretty sure I learned how to derive an equation from a graph in high school. Attached is a graph that should explain how to do it. Also, Google "derive equation from graph".
A tutorial on WHAT? That exact specific question? I'm sure it's out of print. Determining the equation of a line from a point and the slope? Google "equation of line from a point and the slope" How thermocouples work? Google "How thermocouples work" What a Schmitt trigger is? Google "Schmitt trigger" Do you see a pattern, here? Now, if you want to present your efforts, it will give us something to work with. But as long as you just keep posting "give me, give me" demands, you won't get much in return.