Breath-monitor


Posted on Jan 10, 2013

The mercury-in-rubber strain gauge is the detector of breathing. In the model device, the strain gauge produced by Medimatic, Demark was used. The change in the length of the strain gauge wrapped around the chest during breathing causes a varying electrical resistance of about 0.2 0/cm. The constant current passing Rl, R rand R4 gives the constant component on the output of Ul differential amplifier. The change in the resistance of the strain gauge, which results from breathing, produces proportional varying in output voltage of Ul amplifier.


Breath-monitor
Click here to download the full size of the above Circuit.

The voltage follower, based on U2, separates the output voltage of the filter from the input stage amplifier. U3 works as a noninverter amplifier with regulated gain. This device should be supplied with a stabilized constant voltage of ±15 V.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Car Speed limit Alarm
Digital Volume Control with DS1669
Square wave oscillator
3 LED - 1 Cell battery tester
Conversion Receiver For 160 To 20M Circuit
color sensor circuit diagram
Electromagnetic field detectors
500A power switch control circuit diagram
PM4040F application circuit switching power supply drive



Top