# Difference between Difference and Differential Amplifier

1. Apr 27, 2013

### tajuddinkh

Can any body plz explain the difference between difference and differential amplifier as both looks same and its confusing?

Reagrds

2. Apr 27, 2013

### sophiecentaur

Don't let a simple name confuse you. If the two circuits are identical then you can call them what you like - they are still the same. Terminology and categorisation can be a terrible source of worry.

3. Apr 27, 2013

### tajuddinkh

so can i say, actually the difference amplifier is differential amplifier.

4. Apr 27, 2013

### sophiecentaur

Why would you want to? Are you writing an essay on how terms are used in Electronics or do you just not want to uyse the 'wrong' word in a report you are writing? There may be nuances in the way each term is used - a differential amplifier is, afaik, a term used for a building block circuit (OPAmp, for instance - search google and you will probably get a lot of hits for integrated circuit type numbers) and would, perhaps have a very high gain, needing some degree of 'taming' by using feedback. A difference amplifier could possible be a term used for a circuit which gives a usable range of output volts for a useful range of differences between the input signals.

But, really, what is the point of labouring this? It's how things work that counts and the specification of what a circuit does is much more relevant than what actual name you choose to give it. Have you looked around the web to see how the two terms are used?

5. Apr 27, 2013

### tajuddinkh

Basically in our lecture notes the circuit is titled by difference amplifier and explained. in exam paper the same circuit is asked for the name and the name is given differential amplifier by the lecturer and rest of the calculation is same which is for difference amplifier in lecture notes . the confusing bit is in lecture notes there is no differential amplifier. and in google no proper satisfied answer is given and in most of the places both names are drawn by same circuit and equations.

6. Apr 28, 2013

### Runei

I believe you could say that a Difference Amplifier is the specific case where each of the inputs are multiplied by the same amount.

A Differential Amplifier, some inputs might have a greater "weight" than the the others.

So a Difference Amplifier is a special case of the differential amplifier. At least, thats how I have learned to think about it.

It's also discussed here http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/opampvar7.html#c1

7. Apr 28, 2013

### tajuddinkh

thanks you so much. finally i understand the difference. Thanks again.

8. Apr 28, 2013

### sophiecentaur

Or the 'differential' lol

9. Apr 28, 2013

### tajuddinkh

now u r confusing me again.

lolz