# A general question about basic electronics

Discussion in 'General Electronics Chat' started by tonyjms2005, May 19, 2016.

1. ### tonyjms2005 Thread Starter New Member

Jul 23, 2014
21
0
Hello
I am curious to know what would be displayed on an ammeter if:

two sensors were connected in parallel, taking to different readings that would generate -100mA on one sensor and then +200mA on the other sensor.
So basically the current will flow one way through one sensor but then the current will flow the other way generating 200mA, would the resulting reading on the ammeter be 100mA?

Thanks

Antony

2. ### hp1729 Well-Known Member

Nov 23, 2015
2,306
284

Last edited: May 19, 2016
3. ### wayneh Expert

Sep 9, 2010
15,002
5,454
There will be one current in one direction through all 3 devices. The direction will depend on the relative EMFs of the 3 devices. Of course the ammeter has a zero EMF, so it comes down to a fight between the other two. The magnitude of the current will depend on the net EMF and the combined series resistance of the 3 devices.

4. ### tonyjms2005 Thread Starter New Member

Jul 23, 2014
21
0
Hi
Thank you for the replies, basically I have a home built gas turbine engine that I want to improve the combustion chamber, I have a fadec system that I can program to display measured current.

I wish to use 2 A/F ratio sensor from a car (o2 sensors) basically when fuelling is 16:1 the sensor output is 0 mA, is the ratio of air to fuel increases the current output decreases. When the fuel to air ratio decreases below 16:1 the current output decreases into minus figures, or the current flow is reversed.

I am just curious to see if I used them both in parallel to achieve an average.
So if one sensor was outputting 200mA and the other outputting -100mA would I expect to see 100mA reading? Or will I just have to experiment to see?