Question about difference accurate of PCB and breadboard

[lovesaints]

I want to ask is it a sensor circuit build on breadboard are not so accurate if compare to a same circuit that build on a PCB?

Is that possible that component around or behind the sensor also can effect the frequency or the sense area?

 

[WTP Pepper]

PCBs will give a far more repeatable and reliable measurement. Breadboards are prone to RF pickup as all your interlinks are small aerials if you are not careful.
i.e. Your sensor signals could end up running the length of the breadboard picking up allsorts of RF rubbish.

You do not state what sensor we are talking about, but if it's a high impedance sensor or sensing extremely low signals then you need to gain some experience on layout of components and sensitive circuits, ground, power and signal planes and paths.

Sadly this comes with experience or good guidance by someone who know what they are doing. From my experience, many PCB layout engineers do not understand this and will let a computer autoroute where it likes and assume the end result will work as electrically as far as the computers says, is correct - which it will be, but still not work.

 

[KeepItSimpleStupid]

A breadboard has a lot of capacitance compared to a PCB. This can cause issues at high frequencies. It may also provide a small amount of "bypass capacitance". Meaning, you may have omitted bypass caps that are required in the PC design.

 

[lovesaints]

I'm using a 40kHz TX and 40kHz RX and the schematic contains a 40kHz crystal