Dear all
I am doing a design of my sensor circuit, and I need to get y-parameter of BJT in PSpice.
Unfortunately, I am not an Electrical engineer, so it's quite tough to me.
So, if anyone has experience, Plz show me.
Best regards
Dear Nhan,
The most important thing that your transistor is included in the device library.
After calculating its DC operating point you can calculate its small signal parameters and hence its y-parameters. A concept for calculating the y-parameters that you calculate them using simulator as you measure them in the laboratory and you measure them as you define them.
So, if you want to the input y-parameter yi it is defined as yi= Ii/ Vi while the output is made AC shortcircuit.
So, to perform the simulation fro calculating yi you need to make an AC analysis, while applying an AC voltage source, say 1V and short circuiting the output. For common emitter circuit you make short between the collector and the emitter and connect the AC source between the base and the emitter.
Then run the AC analysis while sweeping the frequency in the range you desire, and output the input current Ii, it will be equal to Vi since the AC input voltage amplitude is equal to one volt. You can also plot yi versus frequency.
For the same circuit configuration you can determine forward admittance yf= Io=If/Vi where Io=If is the output AC current in the output short circuit. You can plot it also versus frequency similar to yi.
Likewise you can simulate yo the output admittance and yr the reveres admittance using the same procedure as has been done previously with yi and yf. In this case you put at the output of the transistor an AC voltage Vo= 1V and short circuit the input, then you calculate Io and Ir. By definition yo= Io/Vo and yr= Ir/ Vo.
For more information please refer to the educational materials in the link:https://www.researchgate.net/publication/256346392_The_bipolar_transistors_theory_and_basic_applications
Best wishes
Book The bipolar transistors, theory and basic applications
Dear Professor. Abdelhalim Zekry
You are my Lord
We don't need to the DC-bias voltage for C-E junction? Professor.
If you have a free time, could you please overview my attached paper. In this paper, the author using DC-bias voltage for CE-junction for all case.
P/S: I have already make the highlights in this paper for easily tracking
For the oscillator to operate the amplifier must be biased for class A operation such that it continuously conducting DC currents. I would advise you to read the book which i attached in my first comment.
After seeing the circuit in the paper, the amplifier is biased by a universal biasing which consists of a 10 volt power supply VCC and four resistors, R1,R2, RC and RE. You can make DC analysis to determine the DC operating time. To do that you can follow the method given in the reference above.
If you have any further question please do not hesitate.
Best wishes
Dear Professor. Abdelhalim Zekry
Your attached file is so clear about BJT and its operation mode. Thank you so much, my Lord.
Actually, in my previous attached file, I just only refer to the method for calculating the y-parameter from the output of the simulator ( e.g PSpice ). That means we can get the amplitude and phase of voltage and current from PSpice, and then calculate the y - parameter based on them. I spend all this day to do it and now is OK.
Unfortunately, the new problems come to my simulation. I try to design my circuit based on this paper " Design Considerations of Miller Oscillators for High-Sensitivity QCM Sensors in Damping Media ". I fully understand the method described in this paper.
But my problem is that I can't get the value of "gi" and "gf" from my PSpice simulation which is similar to the value of "gi, gf" in that paper or at least "gf" 0.
I have already attached all my file simulation in Spice including PSpice model of OPA660 from TI, and my Spice file and PSpice 9.2 have already OPA660 model
If Professor is free, please help me. I continuously try to fix these problems.
Best regards
Dear Nihan,
welcome,
would you please send me a circuit diagram of the whole oscillator circuit?
Oscillators can be analysed by calculating their parkhausen criteria or by the negative resistance concept. That is 4 terminal or two terminal circuits.
When i have the overall circuit i can analyse it.
Best wishes
Dear Professor. Abdelhalim Zekry
I did not get feedback from you so I think you have already rejected my problems. ^^
When you come back, I realized that you are really my Lord. -_-
I will check again my oscillator circuit and send it to you soon
Best regards
- Badges
- Science topic
- Similar topics
- Engineering