Pir Module

Right, I brought a passive infrared sensor line fast.
http://www.rapidonline.com/Electronic-Components/Sensors/Pir-Sensors/PIR-Module-with-lens/81565/kw/PIR
The specification of it is in PDF format on the page. There are three rails: power, ground and output. I used it as an NPN transistor, as I think the track would give the output voltage and therefore be used to open a CBC transistor 548B and so on. However, when you use a multimeter, I am negative voltage rail? On the specifications it says it uses an NPN transistor or an 'open collector output (active low). Any information would be amazing, thanks in advance.

Dan

Simply, an output OC is equivalent to an NPN transistor, whose emitter is grounded and the collector is presented to the exit by itself. If the circuit behind the transistor is "active", it puts a positive signal at the base, the "closure" of the transistor, or pulling the output line to ground. When the circuit is "inactive", the output is "open", or just floating.

You can use an OC output in two ways.

First, is to lay a charge, as a relay coil or small LED, the other end for connection to positive rail.

The second is to pull out on the OC supply rail with a resistance of 10K or more. This gives a logic signal for further processing.