Hey guys Im trying to build an amplifier for an accelerometer. using a LM 741 op amp. I also get a lot of noise on the oscilloscope. I'm trying to really amplify the voltage. any suggestions on what set up I can use to? Thanks.

 

What is the part number of the accelerometer to which you are interfacing?

hgmjr

 

256HX Endevco

 

I notice from the datasheet that the sensitivity of the sensor is 10 mV/g. That seems very insensitivity. What is the level of acceleration in g's you are needing to measure?

hgmjr

 

I'm trying to get a measurement of about 2 g's

 

Would you be interested in a more sensitive measurement in the range of +/- 2g?

Also, are you intending to use a microcontroller as part of your project?

hgmjr

 

For the sensitivity yes im interested in 2g's but i wont be using a micro controller.
Ive been trying to recreate the circuit in this website (http://www.me.utexas.edu/~dsclab/labs/accelerometers/ex2.html) varying the resistors according to my gain calculation, but Ive had little success. Any ideas, thanks.

 

I wouldn't use the 741 op amp, it is far too noisy. I would suggest a low-noise instrumentation amplifier. You can find these from Texas Instruments, Analog Devices, and Intersil.

 

Try TL071/NE531/LF351/TL081 all are low noise, hi performance op-amps. Get a low noise op amp for your application. 741 is a general purpose, compensated op amp.

 

Try TL071/NE531/LF351/TL081 all are low noise, hi performance op-amps. Get a low noise op amp for your application. 741 is a general purpose, compensated op amp.

While these will work, an Instrumentation amp will be better. They are generally considered to be "unique op amps" since they provide the same functions of an op amp but provide better performance.

 

For the sensitivity yes im interested in 2g's but i wont be using a micro controller.
Ive been trying to recreate the circuit in this website (http://www.me.utexas.edu/~dsclab/labs/accelerometers/ex2.html) varying the resistors according to my gain calculation, but Ive had little success. Any ideas, thanks.

Once you have boosted the output of the accelerometer adequately, what is your plan for the output of the signal? How do you intend to use the output?

hgmjr

 

If I get this to work.. Im supposed to be measuring small oscillations. kinda like just put the accelerometer on the end of a ruler and pluck the ruler. a small cantilever beam, i want to get the sinusoidal wave for a long beam.

 

If I get this to work.. Im supposed to be measuring small oscillations. kinda like just put the accelerometer on the end of a ruler and pluck the ruler. a small cantilever beam, i want to get the sinusoidal wave for a long beam.

If you are supposed to get oscillations, I would hook the output of the device to an oscilloscope. Then you can see if your getting a applicable waveform corresponding to the correct waveform.

 

yes i have an oscilloscope, i work in a lab.