How Can an Op Amp Circuit Control Constant Current in a Pirani Vacuum Gauge?

Myrddin
Messages
24
Reaction score
0
In a pirani vacuum gauge the pressure is determined by the rate at which heat is conducted away from a resistance wire by gas moleculs. The heat is supplied using a constant current source and the rate of heat dissipation determined by the temperature induced change in the resistance of the wire.

Draw an op amp circuit that can be used to deliver a constant current to an external fixed load resistor. Explain how it works in detail.




Have very basic knowledge of op amp circuits and this question has thrown me, any help will be appreciated. Already posted in engineering section to no avail so far!
 
Physics news on Phys.org
Can you think of any ways to measure the the current through the external fixed resistor in a way the opamp can use?
 
Thread 'Need help understanding this figure on energy levels'

Thread 'Need help understanding this figure on energy levels'

This figure is from "Introduction to Quantum Mechanics" by Griffiths (3rd edition). It is available to download. It is from page 142. I am hoping the usual people on this site will give me a hand understanding what is going on in the figure. After the equation (4.50) it says "It is customary to introduce the principal quantum number, ##n##, which simply orders the allowed energies, starting with 1 for the ground state. (see the figure)" I still don't understand the figure :( Here is...
View full post »
Thread 'Understanding how to "tack on" the time wiggle factor'

Thread 'Understanding how to "tack on" the time wiggle factor'

The last problem I posted on QM made it into advanced homework help, that is why I am putting it here. I am sorry for any hassle imposed on the moderators by myself. Part (a) is quite easy. We get $$\sigma_1 = 2\lambda, \mathbf{v}_1 = \begin{pmatrix} 0 \\ 0 \\ 1 \end{pmatrix} \sigma_2 = \lambda, \mathbf{v}_2 = \begin{pmatrix} 1/\sqrt{2} \\ 1/\sqrt{2} \\ 0 \end{pmatrix} \sigma_3 = -\lambda, \mathbf{v}_3 = \begin{pmatrix} 1/\sqrt{2} \\ -1/\sqrt{2} \\ 0 \end{pmatrix} $$ There are two ways...
View full post »

Similar threads

Engineering Why is the voltage source high potential into node 1 at -12 V in this op amp problem?
Replies
15
Views
2K
Any advice to make this Op-Amp temperature controller circuit work?
Replies
34
Views
4K
Research on HV to UHV vacuum gauge and controller build (Amateur scale)
Replies
1
Views
934
Engineering Draw an op amp circuit with explination
Replies
6
Views
3K
Comparing Op-Amp Parameters: Ideal vs A & B
Replies
3
Views
2K
I have designed a multi op amp circuit
Replies
1
Views
2K
How hot might this 3 amp transformer get?
Replies
10
Views
3K
I Measuring vacuum w/ hot filament - calculation (pirani gauge)
Replies
25
Views
6K
Engineering Op-Amp Circuit Analysis: Voltage and Current Calculations with R1 and R2
Replies
16
Views
4K
AC Current Source: Build an Op-Amp Circuit for µA RMS
Replies
10
Views
4K

Hot Threads

Recent Insights

Back
Top