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Title: spot lights and dc
Post by: jmmrlm on March 06, 2020, 01:27:30 PM

I have miniatronics rail yard spot lights whose instructions say to connect the cable with the diode to the positive connection of the DC output of a transformer .

The power source I am using is the MRC Railpower 1300 that has both DC and AC output terminals. But the DC are not marked positive or negative.

How would I know which is the positive terminal of the DC output on the MRC 1300 in order to follow the Spot light instructions?

Title: Re: spot lights and dc
Post by: Ton N on March 06, 2020, 03:11:45 PM

Depends on how you turn the knob.
backwards is always the reversed polarity of forwards.
But if there is a diode in your circuit it will stop the wrong polarity because a diode is a one way valve for DC

Ton

Title: Re: spot lights and dc
Post by: rich1998 on March 06, 2020, 03:58:14 PM

The DC output is usually not marked. Depends on forward or reverse selection.
You can also use a DC meter to determine.

Rich

Title: Re: spot lights and dc
Post by: Len on March 06, 2020, 04:42:47 PM

You would do better to find a 'wall wart' transformer of the correct voltage to use for the spotlight, rather than the 1300 with it's variable DC output.

Len

Title: Re: spot lights and dc
Post by: jward on March 12, 2020, 06:45:56 AM

Since the diode will convert Ac to the proper polarity DC why not just use the AC terminals?

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Discussion Boards => General Discussion => Topic started by: jmmrlm on March 06, 2020, 01:27:30 PM