Hello guys! I was wondering if you could help me with a class assignment. Right now I am learning about OpAmps configurations, I am trying to modify an output signal coming from a LM35 in order to achieve a 1V at 30°C and 5V at 100°C output.
I am not sure if I am doing this right so your help will be appreciated.
The LM35 Datasheet shows that the Volt/Temp output works with a 10mV / °C linearity. That means that at 30°C Vout = 300mV. So first I need to add 700mV to get 1V at 30°C (I know I can do that just adding a constant input of 700mV from another source).
But here's the problem, so far I know that between 30°C and 100°C I have a 70°C gap, and also from 1V to 5V there's a 4V gap which means I must add a (4/70) factor for every °C which gives:
For me it seems like I need a variable Gain to get something like: 1V + n(4/70)=Vout where n is the gain and varies from 1 to 70, and I dont know if a configuration like that is possible.
Another solution might be just multiplying each 10mV for a 4/70 gain but as input I'll just have values like 310mV, 320mV, 330mV and the linearity will be lost ( is there a way to just take that 10mV difference per °C?)
I am pretty sure there's an easier way to do it but I've been struggling with this, and that's why I am asking for help. Thank you!
I am not sure if I am doing this right so your help will be appreciated.
The LM35 Datasheet shows that the Volt/Temp output works with a 10mV / °C linearity. That means that at 30°C Vout = 300mV. So first I need to add 700mV to get 1V at 30°C (I know I can do that just adding a constant input of 700mV from another source).
But here's the problem, so far I know that between 30°C and 100°C I have a 70°C gap, and also from 1V to 5V there's a 4V gap which means I must add a (4/70) factor for every °C which gives:
For me it seems like I need a variable Gain to get something like: 1V + n(4/70)=Vout where n is the gain and varies from 1 to 70, and I dont know if a configuration like that is possible.
Another solution might be just multiplying each 10mV for a 4/70 gain but as input I'll just have values like 310mV, 320mV, 330mV and the linearity will be lost ( is there a way to just take that 10mV difference per °C?)
I am pretty sure there's an easier way to do it but I've been struggling with this, and that's why I am asking for help. Thank you!