- #1
Femme_physics
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Question at topic title.
How to Prepare for a Job Interview""Preparing for a Job Interview: Tips & Advice
In summary, an opamp without a power supply will have no current flowing through its output, since there is no way to bias the output transistors.
- #2
Kholdstare
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Supply voltage is needed to bias the output transistors. Without it the OPAMP output transistors will be all off and the output node will be have high input impedance. i.e. Whatever voltage the outside circuit tries puts on the output node it will keep that voltage.
- #3
Femme_physics
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So no supply voltages = no current at all?
I'm talking about an amplifier with no feedback btw
- #4
AlephZero
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Femme_physics said:
That depends entirely on the chip design, but it's a hypothetical question, because active electronic circuits (e.g. op amps) are only designed to be used when the power supplies ARE connected.
- #5
jim hardy
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Just assume all opamps have to be powered. Any that draw their power from input pins instead of V+ and V- pins are special cases.
When National Semiconductor published their AN31, OP Amp Collection, it didn't show the power pins. They got so many inquiries from newbie experimenters who had neglected to power their circuits they put out a special bulletin to that effect.
AN31 is really old now but those guys were geniuses and the design of their circuits is quite instructive.
It's a great introductory learning tool, as is TI's "OpAmps for Everyone".
One can use modern opamps in these old circuits.
AN31: http://www.ti.com/general/docs/lit/getliterature.tsp?svadoc=an-31®=en
OPAmps for Everyone: http://www.google.com/url?sa=t&rct=...QxYdkL4XemccjuNYQ&sig2=SsJrqlAmpgf3c7JV7uzt3w
or search on "opamps for everyone" slod006
It's a 464 page textbook in pdf that should be printed and kept in one's technical library.
When National Semiconductor published their AN31, OP Amp Collection, it didn't show the power pins. They got so many inquiries from newbie experimenters who had neglected to power their circuits they put out a special bulletin to that effect.
AN31 is really old now but those guys were geniuses and the design of their circuits is quite instructive.
It's a great introductory learning tool, as is TI's "OpAmps for Everyone".
One can use modern opamps in these old circuits.
AN31: http://www.ti.com/general/docs/lit/getliterature.tsp?svadoc=an-31®=en
OPAmps for Everyone: http://www.google.com/url?sa=t&rct=...QxYdkL4XemccjuNYQ&sig2=SsJrqlAmpgf3c7JV7uzt3w
or search on "opamps for everyone" slod006
It's a 464 page textbook in pdf that should be printed and kept in one's technical library.
- #6
NascentOxygen
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Another puzzle from the questioning mind of Femme_physics!Femme_physics said:
There is no feedforward in an unpowered op-amp (well, none that can be relied upon, anyway!) So the output cannot be powered by the input in the manner you are picturing.
No supply voltage/s = no usable output
- #7
Femme_physics
Gold Member
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:) hehe
Gotcha! Thanks.
And also Jimhardy and alephzero--thanks for the "feedbacks":) (my jokes used to be better)..
1. What should I research before a job interview?
Before a job interview, it is important to research the company, the position you are applying for, and the person or people who will be conducting the interview. This will help you to understand the company's values and goals, the specific responsibilities of the job, and the interviewer's background and role within the company.
2. How should I prepare for common interview questions?
To prepare for common interview questions, you should research commonly asked interview questions for your specific industry and practice your answers. It can also be helpful to think of specific examples from your past experiences that demonstrate your skills and qualifications.
3. What should I wear to a job interview?
It is important to dress professionally for a job interview. This typically means wearing business attire, such as a suit or dress pants and a blouse for women, and a suit or dress shirt and tie for men. Make sure your clothes are clean, pressed, and fit well.
4. How early should I arrive for a job interview?
It is recommended to arrive 10-15 minutes early for a job interview. This will give you time to check in, use the restroom, and compose yourself before the interview. Arriving too early can be seen as disrespectful of the interviewer's time.
5. What should I bring to a job interview?
You should bring a copy of your resume, a list of references, and any relevant documents or samples of your work. It can also be helpful to bring a pen and notepad to take notes during the interview. Make sure to also bring any necessary identification or paperwork requested by the company.
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