i used a tmp36 temperature sensor but when i touched the pin in the middle with a wire or a mulitmeter probe the voltage dropped from 0.71 V to 0.69V. when i use a capacitor between V+ and the middle i don't get such a drop - but i don't know why this is working with the capacitor at this position.
can somebody explain this to me?
Hi, without the capacitor, when you used the probe it acts as an aerial and places noise on the output pin, this causes your measured voltage to change.
The capacitor filters the noise and so the arduino measures just the output.
As a suggestion, filter capacitors are usually between the output pin and ground.
Tom..... 
i tried it between output and ground but it didn't work. this was the only working version... for whatever reason
