En clair dans le cas d'un simple face, les 2 fils seront amenés en parallèle avec un faible écart entre eux. Dans le cas du double face, un fil coté composant, l'autre coté soudures juste en dessous suivant le même chemin.
Sinking sensors allow current to flow into the sensor to the voltage common, while sourcing sensors allow current to flow out of the sensor from a positive source. For both of these methods the emphasis is on current flow, not voltage. By using current flow, instead of voltage, many of the electrical noise problems are reduced.
When discussing sourcing and sinking we are referring to the output of the sensor that is acting like a switch. In fact the output of the sensor is normally a transistor, that will act like a switch (with some voltage loss). A PNP transistor is used for the sourcing output, and an NPN transistor is used for the sinking input.
It is confusing, not the least because they use conventional current flow rather than electron flow which reverses the sense of source/sink. It's easiest to think of it in these terms. With a positive supply voltage, a normally biased PNP will have its emitter more positive than its collector. So, a PNP output with an open collector will pull a load positive towards the supply voltage when conducting. This gives what is called a sourcing output. The NPN case is opposite so it's collector will take a load towards ground when conducting. That's why PNP and NPN are sometimes used instead of sourcing/sinking, because they are not ambiguous at least with open collector outputs. Inputs get a little more confusing as some can be strapped to be either sinking or sourcing. In general, a sinking input is one that needs to be pulled up towards the positive supply to be true. And a sourcing input is one that needs to be pulled toward ground to be true. So a Sourcing output would normally be used with a sinking input and vice versa. This all assumes positive logic
An NPN or sinking output accepts voltage and sinks it to ground to complete the circuit. A PNP or sourcing output sources voltage and the external circuit sinks it to ground to complete the circuit. A sourcing circuit would be drawn as voltage→switch→load→ground. A sinking circuit would be drawn as Voltage→load→switch→ground. In these cases, the switch could be a transistor.
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