One pot symbol is all you need. You change the value and the percent rotation.once it's on the schematic.
Version 4
SymbolType CELL
LINE Normal 16 88 16 96
LINE Normal 0 80 16 88
LINE Normal 32 64 0 80
LINE Normal 0 48 32 64
LINE Normal 32 32 0 48
LINE Normal 16 16 16 24
LINE Normal 16 24 32 32
LINE Normal 40 64 64 64
LINE Normal 40 64 48 56
LINE Normal 40 64 48 72
WINDOW 0 36 32 Left 0
WINDOW 3 36 88 Left 0
WINDOW 39 36 128 Left 0
SYMATTR Value Rtot=10K wiper=.5
SYMATTR Prefix X
SYMATTR SpiceModel potentiometer
SYMATTR Description Resistor Potentiometer, must include potentiometer.sub
SYMATTR ModelFile pot.sub
PIN 16 16 NONE 0
PINATTR PinName A
PINATTR SpiceOrder 1
PIN 16 96 NONE 0
PINATTR PinName B
PINATTR SpiceOrder 2
PIN 64 64 NONE 0
PINATTR PinName C
PINATTR SpiceOrder 3* This is the potentiometer
* _____
* 1--|_____|--2
* |
* 3
*
.SUBCKT potentiometer 1 2 3
.param w=limit(wiper,1m,.999)
R0 1 3 {Rtot*(1-w)}
R1 3 2 {Rtot*(w)}
.ENDSI got my EE in 1966. I retired in 2007. Two old farts.I would probably take out the cap and see if it still acts the same, but that's just me. You could also go by the old adage, "If it works, don't fix it.".
Hysteresis is calculated by simple math. It's just the change in voltage at the noninverting input when the output switches. In this case, first calculate the voltage swing at the comparator output. Since R6>>R5, you can safely ignore R6 for this calculation. The swing will be from ≈0V to ≈1.4V, or about 1.4V p-p. This gets attenuated by the network consisting of R6, R9, and the resistance looking into the pot wiper. The wiper impedance varies from zero to about 8k, depending on where it is set. Thus, your present hysteresis is approximately
Vh=1.4*((R9+Rpot)/(R6+R9+Rpot). This calculates out to be a range of 88mV to 150mV.
Actually, the circuit won't trigger when the wiper is at max voltage, but simulation shows Vh=152mV with the pot voltage at minimum, almost exactly what I calculated.
If you try to leave R9 at 10k, the change in pot resistance will cause your hysteresis to vary even more wildly if you lower the value of R6. That's why I suggested changing R9 to 100k.
Too much information here.
What range do you want for the threshold when the input voltage is rising? How much hysteresis do you want? Or do you want the threshold to drop to 3.65V, independent of the rising threshold?Too much information here.
The definition of hysteresis is a delta (change in) voltage.
So, independent of the threshold voltage, you want the relay coil current to go off when the sensor voltage goes above the threshold voltage, and stay off until the sensor voltage drops below 3.65V. Am I interpreting this correctly?
OK, I looked at the PDF you PM'ed. Have you noticed that it is very similar to your circuit? If you add the voltage regulator, which I recommended, it is even closer. You could get rid of the zener if you add the regulator.
I'm working on it. I've been busy on other stuff today. I might get back to it tomorrow afternoon.
