Help with smoothing capacitor for LED dimmer

[refugio]

In a discussion on docking lights I mentioned that I needed to smooth my dimmed LED cabin lights, and I ended up getting these smoothing capacitors:

SODIAL(R) 5 x 25V 1000UF 105C Radial Electrolytic Capacitor 10x20mm

Q1: Does the silver stripe with large "-" mean these are polarized and that's the negative side?

I'm going to install these in this circuit (where my "lamp" is a 12vdc LED light fixture that flickers when I'm plugged into shore power and charging):

Q2: Where does the capacitor go? Looking at other sample circuits on the web it looks like it should go between the RED and BLACK wires - I'm thinking that the dimmer is a variable resistor and all of the diagrams show smoothing capacitors before an inline resistor. But I could also see putting it between the BLUE and BLACK wires.

Any guidance appreciated.

 

[TG]

Yes, you have a polarized capacitor and the stripe with the minus sign should go to ground. Typically the positive lead is longer and the negative shorter.

I don't see a problem with filtering both the input and the output.

Worse case is it doesn't do anything or maybe it won't dim.