Do circuits built using PCB and using bread board perform the same?

[yungman]

Yungman, I recall hearing that prior to my employment freon was often used for cleaning boards. I never had any experience with it.

We mostly use the bath for high vacuum components. We kind of taking advantage that of the situation and use it. Now is almost impossible to buy those freon anymore because of the pollution.

 

[yungman]

Just a wild hunch, put a temporary spacer ( like a piece of cardboard) under the relay when you solder to create a tiny gap between the pcb and the relay when you solder. Then remove the spacer after soldering. Now you have some day light between the relay and the board. With this, dirt, flux is not going to be trapped as easy and you can get the flux solvent in between and clean the flux or dirt.

 

[yungman]

One thing not mentioned here but certainly is an issue in very sensitive applications is piezoelectric effects. With breadboards, everything is through hole and loosely mounted so piezoelectric effects can be ignored. However on PCB's, SMD mount capacitors can function as little microphones and introduce electrical noise from acoustical vibrations from the local environment.

Some of my research requires very sensitive optoelectronics (talking GIGA-ohm feedback resistors on op-amps here) where just clapping your hands in the same room as the device would completely wash out the signal being measured. These kinds of things can be ignored in most cases, but in my case I had to go back redesign an enclosure and part of a PCB due to not taking these effects in account.

It's the vibration. We deal a lot with that. that's where rigid coax and secure mounting come in play. In fact I was helping a person here on photo diode detector circuit. He had the photo diode mounted on a platform moved by stepper motor, he used cable to connect to the transimpedance amp mounted somewhere else. I had him move the whole transimpedance amp to the platform with the photo diode and solve the problem. Get as much gain on the rigid part before sending the signal down. Have the amp bud up to the detector to minimize the components that can pick up vibration. At that, it is not a guarantee.

 

[Averagesupernova]

Yungman, the final fix for the flux residue under the relay was in fact a spacer that did what you described. The vapors escaped during soldering and did not impregnate the plastic on the relay. As I remember it, once the relay was contaminated there was little that could be done to clean it up. It had become part of the plastic.