Hi all,

Im new here :huh:

Ive got a problem, lab report due tomorrow, my fault for leaving it so late but have been snowed under with other work.

just about finished it, but having to return to a bit i missed out.

here is the background - built an Intruder alaram system - detects sounds through mic and if over a certain threshold then signals the alarm, was designed to connect to a motion (ultrasound) detector through an oscillator.

here are the modules:
receiver >> invert op amp >> rectifier >> comparator >> oscillator >> led/buzzer

one of the points i need to answer is:
"explain what is meant by the gain bandwidth product of a closed loop amplifier and its significance for this project".

i calculated the GBP to be 750Hz but no idea why - got a table of results, is it something to do with half of some quantity?

I never realised the importance of a decent lab book until now - i am only in first year and am still learning.

please help and save my day

iain
uk

 

pritty please

 

Hi Cranny
am not a geek myself. But I could make an attempt at answering ur question. Gain Bandwidth product indicates the gain of a device at a particular frequency.
It is usually associated with amplifiers, which require you to generate certain amount of gain. By saying the GBP for an amp is 1 MHz, all it means is that the amplifier can give a maximum gain of unity at 1 MHz.

Hope this brings u out of troubled waters

Shreyas

Originally posted by cranny@Feb 28 2005, 05:43 PM
Hi all,

Im new here :huh:

Ive got a problem, lab report due tomorrow, my fault for leaving it so late but have been snowed under with other work.

just about finished it, but having to return to a bit i missed out.

here is the background - built an Intruder alaram system - detects sounds through mic and if over a certain threshold then signals the alarm, was designed to connect to a motion (ultrasound) detector through an oscillator.

here are the modules:
receiver >> invert op amp >> rectifier >> comparator >> oscillator >> led/buzzer

one of the points i need to answer is:
"explain what is meant by the gain bandwidth product of a closed loop amplifier and its significance for this project".

i calculated the GBP to be 750Hz but no idea why - got a table of results, is it something to do with half of some quantity?

I never realised the importance of a decent lab book until now - i am only in first year and am still learning.

please help and save my day

iain
uk

[post=5713]Quoted post[/post]​

 

Well, if you have a GBP of 750 Hz, it means that ur amplifier can produce a max. gain of 1 at 750 Hz.
I presume ur sound detector should operate at certain frequencies (presumably the human audible range - 20 to 20000 Hz). From what I understand, ur ckt. will not amplify signals over 750 Hz (although they fall in the audible range). Therefore, this is of great concern. An alternative could be the use of a High Gain Bandwidth op-amp.