readout for accelerometer

E

engr_joni_ee

Advanced Member level 3
Joined
Nov 3, 2018
Messages
750
Helped
2
Reputation
4
Reaction score
4
Trophy points
18
Activity points
6,233
I am working at the readout of the piezoelectric accelerometer B&K 4516 which needs a current source between 2 mA to 20 mA. Do we have any reference design with components that delivers constant current to the piezoelectric accelerometer ?
 

Sort by date Sort by votes
Hi,

what about doing an internet search on your own for "current source schematic"?
Did you contact the manufacturer for support?

Klaus
 
Last edited:

Upvote 0 Downvote
Due to the wide current range, a stable voltage source with series resistor will already work for the purpose, at least for a first test, You'll probably end up with a simple transistor current source.
 

Upvote 0 Downvote
A question is whether the current "can vary 2-20mA
as it pleases, no prob" or "can be anywhere in that
range, but then must stay put". The former, call it a
resistor.
 

Upvote 0 Downvote
Pick any current between 20 and 20 mA and make it a precision low-noise high impedance constant current source over the entire vibration spectrum for the CCLD active accelerometer with a built-in charge amp that translates the output into mV/g.
 

Upvote 0 Downvote
I found LM317 adjustable which can be used to deliver 12.5 mA current with R1 100 Ohm. Additionally I have drawn how to connect the accelerometer and oscilloscope for probing. Kindly have a look and let me know if any thing missing. Thanks in advance.
 

Attachments

  • Untitled 401.png
    32.9 KB · Views: 39

Upvote 0 Downvote
We have slow acceleration which we need to measure. I am not sure about the values but what is the bandwidth of measurement if we use LM 317 current source solution. ?

Have a look at the circuit diagram again I provided in the last post. If due to acceleration the voltage across the accelerometer is change, how about the current ? would it be constant through LM 317 current source in to the accelerometer ?
 

Upvote 0 Downvote
According to LTspice model, LM317 has 1 MOhm output impedance below 1 kHz, falling factor 10/decade at higher frequency. Should work well for your application.
 
Upvote 0 Downvote
joniengr said:
If due to acceleration the voltage across the accelerometer is change, how about the current ? would it be constant
Click to expand...
Basically that´s the idea of a constant current source ....


Mind:
For the current source to work properly it needs sufficent high input voltage.
If I´m not mistaken then the accelerometer has a bias voltage output of about 10V.
If so, then its a good idea to choose the total supply voltage to be a bit higher than 2 x 10V = 20V.

Klaus
 
Upvote 0 Downvote
You must log in or register to reply here.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…