Tagged Questions

80 views

Op Amp gain less than 1?

How would I design an op amp with a gain of less than 1? Is this even possible? Also would it matter if I used a non inverting or an inverting op amp? I've designed a non-inverting op amp with a ...
61 views

According to page 15 of AD811 datasheet , it can be used as a voltage controlled amplifier in conjunction with AD834 . In the schematic below, I am a bit confused about the configuration. If we ...
141 views

How to control the gain of FET/BJT/Op-Amp amplifier by input voltage range?

Assume I have an input voltage ranging from 5-10 MHz and want to amplify it. The case is pretty simple as any device as FET,BJT or high frequency op-amp can do the amplification well but I have a ...
196 views

How to design a unity gain with LM358 op amp?

I am trying to get a unity gain out of an LM358 to increase the current of an AC sine wave input from 5mA to something slightly higher. I thought I had it hooked up correctly for unity gain, but most ...
258 views

I have to make an ADC conversion with an ATXmega MCU, in an air quality application. The input is a voltage divider between a voltage reference. The sensing resistor vary in relation to a gas ...
231 views

How can I modify this circuit for a higher gain?

Here is an image of an amplifier circuit. How can I modify this for a 10-50 times more gain. I put a wire from pin 1 to 8, but I didn't get enough gain.
284 views

Gain on a Differential Amplifier

For the past hour, I've been trying to calculate the gain of a differential amplifier in the following form: $\frac{V_{out}}{V_{in}} =$ some function of resistors I went to this site and tried to ...
1k views

How do I calculate the gain of an op-amp summing amplifier?

So if I have a summing amplifier circuit like the one below: I know the Vin1, Vin2, and Vout value and the circuit is designed such that Vout = -(Vin1+2Vin2) but how do I calculate the gain? I know ...
634 views

Why is my instrumentation amplifier's gain non-linear?

I am using an AD8226 instrumentation amplifier as the pre-amp in a circuit which uses a micro fuel cell oxygen sensor to measure oxygen content in a gas stream. The pre-amp is configured in single ...
189 views

What does it mean for amplifiers to be stable only down to N gain, where N > unity?

This is related to What's special about "unity-gain stable"? which is about unity gain stability. But what exactly does it mean if some op-amp is said to be only stable to, say, gain ...
270 views

Characterizing raw op amp gain

I thought as a first exercise in op amps, even before setting up a feedback circuit, I would determine the gain of the raw op amp. I tried with an LM324 and an LM358 which should be essentially the ...
267 views

Analog Switch Breakdown voltage?

I'm designing a select-able gain circuit using a multiplexer and an inverting amplifier. Here's an example circuit, using a multiplexer. I've read that if you provide a voltage larger than the ...
424 views

Op-amp gain too big, can't figure out why

We are using a 741 opamp using an inverting input. My students built a circuit, and the gain was way too high. They had taken it apart. So I had them build it in front of me. The gain is still too ...
207 views

OP AMP amplifier [closed]

I am building a simple op amp amplifier circuit using IC LF351. I m using this circuit at very low voltages about 100mV. however the gain does not remain the same at this voltage. Like the theoretical ...
442 views

Is feedback transfer function the same as the transfer function for the whole circuit?

I have a circuit very similar to the inverting band pass filter circuit here: I was asked a question about the circuit's feedback transfer function. Is this the same as the transfer function for the ...
181 views

Types of amplifier - what is the difference?

What is the difference between an open loop amplifier and a voltage follower (unity gain buffer)?
322 views

OP07 unity gain

Is an OP07 unity gain stable ? I am powering it with a +/- 5V supply. I am using it to buffer a DC signal which varies slowly. Most of the modern Op-amps have their datasheets mentioning them ...
156 views

Is there an amplifier such that the gain is equal to the ratio of two potential differences?

I have been toying with some alternatives to transistors in building logic gates. I am particularly interested in the device I tried to summarize in the title of this post. The chip would have 8 pins: ...
1k views

Switching op-amp gain resistances - how?

Given the following circuit: What is the component / circuit I should be using to switch the signal between each of the gain resistors? (the ⊠s in the schematic) The inputs ID0 to ID2 are TTL ...