- #1
edmondng
- 159
- 0
Hello everyone,
I'm trying to find more information to get a better understanding on capacitors. I made a small parallel plate capacitors basically to use it as a sensor and for data collection/analysis to see if there is any correlation with my ongoing research.
The capacitor formula C= (epsilon*A)d does not tell anything about the conductivity of plates (material used), nor talks about any side plates. After gathering some information, and comparing it with my calculation, I'm more confused than ever. I'm posting in physics because some of the answers might just boil down to electrons, e-field, maxwell etc
Questions:
1. The capacitance goes down if you put a conductor inside the plates or move your hands near it. I suppose this is causing the electrons drift elsewhere creating less e-field?
2. I compared readings between having side plates/top plates and with the parallel plates (basically having a cube of 6 sides) with just 2 side plates. The readings differ from 15pF (with just 2 plates) to 60pF (cube with 6 sides).
Why is that? Is it because with the side and top plates it is containing the e-field thus reducing stray capacitance? Again the formula does not say anything about side plates but most books show capacitors built with just the 2 parallel plates and i suppose they are assuming d is so small. My d is approx 2inches
3. The inductance of my parallel plate capacitor decrease when i increase the frequency. Also I read in the manual it says capacitance measurement accuracy increase when increasing frequency. Why? I thought with a higher frequency the capacitor acts like a short. Isn't capacitance a measure of how many e- can be stored with some potential applied? The higher the capacitance, the more energy or e- are stored.
Inductance suppose to resist change so it should go up (unless I'm contradicting myself here between impedance of capacitor and inductor and would just need to fix Zc, so if Zc goes down and Zl = Zc then L goes down?)
Please move this if its not in the right place. Just wanted some ideas, explanation on some of my questions. If would be helpful if could answer some of my questions or point me to the right information.
Thanks for your time
I'm trying to find more information to get a better understanding on capacitors. I made a small parallel plate capacitors basically to use it as a sensor and for data collection/analysis to see if there is any correlation with my ongoing research.
The capacitor formula C= (epsilon*A)d does not tell anything about the conductivity of plates (material used), nor talks about any side plates. After gathering some information, and comparing it with my calculation, I'm more confused than ever. I'm posting in physics because some of the answers might just boil down to electrons, e-field, maxwell etc
Questions:
1. The capacitance goes down if you put a conductor inside the plates or move your hands near it. I suppose this is causing the electrons drift elsewhere creating less e-field?
2. I compared readings between having side plates/top plates and with the parallel plates (basically having a cube of 6 sides) with just 2 side plates. The readings differ from 15pF (with just 2 plates) to 60pF (cube with 6 sides).
Why is that? Is it because with the side and top plates it is containing the e-field thus reducing stray capacitance? Again the formula does not say anything about side plates but most books show capacitors built with just the 2 parallel plates and i suppose they are assuming d is so small. My d is approx 2inches
3. The inductance of my parallel plate capacitor decrease when i increase the frequency. Also I read in the manual it says capacitance measurement accuracy increase when increasing frequency. Why? I thought with a higher frequency the capacitor acts like a short. Isn't capacitance a measure of how many e- can be stored with some potential applied? The higher the capacitance, the more energy or e- are stored.
Inductance suppose to resist change so it should go up (unless I'm contradicting myself here between impedance of capacitor and inductor and would just need to fix Zc, so if Zc goes down and Zl = Zc then L goes down?)
Please move this if its not in the right place. Just wanted some ideas, explanation on some of my questions. If would be helpful if could answer some of my questions or point me to the right information.
Thanks for your time