Op-Amps Interview Questions 

Hey I heard you can take a cordless drill battery charger and get it to convert 12VDC to mains voltage (here thats about 240VAC ~50hz?) anyway I'm hoping its possible to do it with a computer PSU...I was thinking I could rip out the controller and just use the inductors to get what I want....I'm guessing the voltage rails are done by an OP amp? any ideas of where to look for this project?

The idea for use is to take 12VDC from my car to run my stereo :) I have a feeling the AC-DC rectifier might not work in reverse :(

I am using labview to record pressures measured from transducers. I hooked an op amp up to the transducer output because it maxed out at 24mV and I needed it to range between 1 and 10 Volts.

Now the op amp is amplifying the very slight fluctuations in the (DC) voltage. What once was barely noticeable fluctuations (+- 0.3mV) is now being amplified roughly 210 times, and is on the order of +-10-20mV!

I have tried using a low pass filter to get rid of some of the fluctuations, but it either does nothing or stops the voltage from changing with pressure. Any advice?

R1=20kO and RF = 600kO. The op-amp parameter are A0 = 2x105, fO =10Hz, RO=100O, and Ri =2MO. The frequency of the input signal is fs=10 kHz. Determine the unity gain bandwidth fbw, the closed loop voltage gain Af and the closed loop break frequency fc of the op-amp

http://img238.imageshack.us/img238/3626/...

With no load resistor across the output terminals of the amplifier, and Vin = 0.25 V, the output voltage, Vout = 5 V. With a resistor of 50 O across the output terminals, Vout = 2 V. What is the output resistance of the op-amp?

Thanks in advance!

Can this (http://www.datasheetcatalog.org/datashee... quad op amp work as an inverter if you follow the Vcc being +5 and the GND being Ground (0V)??

Its marked different than most amplifiers and seems to desire only +5 and ground, but for some reason I cannot invert a +4V signal to a -4V signal....is this out of this particular op amp's scope?

hi friends, I'm doing university project concerning the converting the Transistor transistor logic(TTL) signal to Nuclear Instrumentation Module(NIM) signal. Here is my question,

1) i got the output square wave at the logic 0 recorded 600mv and logic 1 is -20mv. the result i wish to get is logic 0 record (range 1v to 0volt) and logic 1 is (-1.8v to -0.6v)...how to increase the gain of the level?by using operational amplifier? which type of op-amp i have to use?

2) Beside the addition of op-amp, what else i can do for my circuit in order to increase the level of the output?

3) the circuit i refer to was at the link below

lyoinfo.in2p3.fr/cms/cmsecal/TTL_NIM%2...

4) Beside that, is it the capacitor and resistor which are in parallel with each other will influence the output?

5) which part of the circuit will play major in the translating the

Op-Amp's integrator.

An op amp has the following specifications:

op amp used as a comparator
–18 V < VSupply < +18 V
maximum difference in supply voltages = 32 V
supply voltages are +15.2 V and –15.2 V
rail headroom voltage = 1.1 V (for both + and – supplies)
A = 1.5*106
maximum output current = 21.9 mA.

The input voltages are Vni = 3.8 mV and Vinv = 13.7 mV.

The output voltage of the op amp is _______ V.

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completely lost

What is the difference between these 3 formulae?
I know they are essientally the same but they use in different situation. Could anyone explain to me please?

P=V*I
P=V*V/R
P=I*I*R

Because for example, I don't know why for an op amp, it should have high input R and low output R.

I want to build a buffer amplifier to monitor a 0-5 volt dc signal from a high impedance source.
Amp input should be high impedance to minimise effect on source.
Any suggestions for suitable op-amp chip? .

Gain and bandwidth of an op amp is
a) Independent of each other
b) Gain decreases as bandwidth decreases
c) Gain increases as bandwidth increases till some extent after which stability decreases

I am trying to find a data sheet for High Frequency Osc . I am asked to select an op-amp for a circuit and it is High Frequency Osc . Where can I find it ? I have been looking for 6 hours now and still can't find it please help me I am so tired.

With no load resistor across the output terminals of the amplifier, and Vin = 0.25 V, the output voltage, Vout = 5 V. With a resistor of 50 O across the output terminals, Vout = 2 V. What is the output resistance of the op-amp?

Thanks in advance!

I need some help wiring up an quad-op IC. I'm new to circuity wiring. How do you wire the negative voltage for the op-amp. I currently have a dc voltage going to a 12 voltage regulator for the +12, but how would i get the -12v.

-"we suggest that you couple the output of the transmitter
to the input of the receiver through a 15 pF capacitor"
-what do you mean when you say "couple"?


-"Place 0.1 uF decoupling caps between the power supply pins ( 4 and 7 of LM741) and ground."
-does this mean that pins 4&7 of the op-amp are shorted, and a decoupling capacitor is connected to these pins and to the ground? what is a decoupling capacitor?