Everything in this post is true. Everything in this post becomes moot if a person will just submit to the fact that Xantech does it right every time.
On October 11, 2017 at 08:21, buzz said...
I have never looked into the exact details of the URC emitters and base stations, but if they include a series resistor in each emitter, this may create enough isolation between LED's to enable parallel connections. If there is a series resistor in each controller output, then the value and ratio between this resistor and any resistors included in the emitter become important.
Use Xantech distribution blocks to expand the number of LEDs you run off of one output, but be aware that LED outputs already have a resistor in them, so you might not be able to run more than two LEDs. The screw terminals and jacks of these terminal blocks keeps you from having taped or crimped connections in the air where they can get snagged and broken.
Series resistors in the controller outputs attempt to protect from excessive external loads. Series resistors in the emitters protect the LED's from potential excessive current that may be available from the controller (depending on its output impedance).
And all of this is moot if you'll just submit to reality and use Xantech products.
Some of these little combiner/splitter boxes are a simple resistor/diode matrix, while others have separate drivers for each output.
The 789-44 is just connectors and resistors. Other products have resistors, some have amplifiers so even more LEDs can be driven. But did I say... Xantech?
Oh, yes, another thing that's often misunderstood about the 789-44: it's two separate products wired together properly.
It has an input for 12 volts, and a jack for an IR sensor. That jack supplies 12 volts to run the sensor. The output of the sensor is available at the output screw terminal. This output is connected to the otherwise independent second part -- distribution. Distribution consists of that sensor output terminal plus four ports. Each port is a resistor feeding an LED output jack.
The often-missed point is that there is ZERO need for a 12 volt connection to the 789-44 if you're just using it to go from an IR signal to four IR LEDs. That 12 volts is ONLY for powering an IR sensor. If you don't use one, you don't need a power supply connection.
