Hello all,
I am trying to work through some of my predecessors work and I have come across this.
There's a thermistor in a potential divider, I cannot tell if the thermistor is R1 or R2.
The formula is then passed through something that look similar to the Steinhart & Hart equation...
This is what I have in Excel.
=3988/(LN(((($D$26*4990)/($D$26-D29))-4990)/10000)+3988/298)-273
3988 being the thermistors B value.
D26 being 5.09V
D29 being the voltage from the potential divider
4990 being the fixed resistor in the divider
10000 Thermistor R at 25C
273 is the conversion from K to C (298 is K at 25C)
(replaced excel bits to make more readable)
=thermB/(LogN((((Vin*R1)/(Vin-Vtherm))-R1)/RT25)+thermB/K25)-273
I have tried to pull out and break down the voltage to resistance conversion here and tried to compare it to the normal formula's
R1 = -(R2(Vout-5)/Vout)
and R2 = (R1(Vin - Vout)/Vout)
But the numbers do not match.
Can anyone enlighten me here?
Thanks.
I am trying to work through some of my predecessors work and I have come across this.
There's a thermistor in a potential divider, I cannot tell if the thermistor is R1 or R2.
The formula is then passed through something that look similar to the Steinhart & Hart equation...
This is what I have in Excel.
=3988/(LN(((($D$26*4990)/($D$26-D29))-4990)/10000)+3988/298)-273
3988 being the thermistors B value.
D26 being 5.09V
D29 being the voltage from the potential divider
4990 being the fixed resistor in the divider
10000 Thermistor R at 25C
273 is the conversion from K to C (298 is K at 25C)
(replaced excel bits to make more readable)
=thermB/(LogN((((Vin*R1)/(Vin-Vtherm))-R1)/RT25)+thermB/K25)-273
I have tried to pull out and break down the voltage to resistance conversion here and tried to compare it to the normal formula's
R1 = -(R2(Vout-5)/Vout)
and R2 = (R1(Vin - Vout)/Vout)
But the numbers do not match.
Can anyone enlighten me here?
Thanks.