S-Runner posted:I can understand using the DC-DC Buck Converter to adjust a Menards DC 4.5 volt wall power supply down to something less than 4.5 volts DC. But the photo appears to show you taking the AC-DC Buck Converter output and then going directly into the DC-DC Buck Converter. So, what's the benefit/use of the DC-DC Buck Converter?
Apparently, to get the desired dimming performance, you have to lower the voltage to 2.7V DC. Many of the AC-to-DC modules only go down to 3.3V...including the one suggested earlier:
I don't know if that is THE reason 2 converter modules (AC-to-DC followed by a DC-to-DC) were used when perhaps only one (AC-to-DC) is required.
Separately, while we're only talking about a few dollar difference, note that you can buy a 2-wire DC voltmeter for around a buck. So you can simply attach this to the output of whatever regulator module that does not have an integral meter. Note that these operate down to 2.7V which is apparently as low as you need to go for Menards buildings.
I realize there is a simplicity benefit to using the AC auxiliary/accessory output voltage that many train transformers provide. But, in general, any power used by the AC auxiliary transformer output steals from the total available power of the transformer so the mainline track power is compromised. The point being you can buy ridiculously inexpensive DC power sources such as 12V DC wall-warts for less than 10 cents per Watt. These could then drive the DC-to-DC regulator modules with integral DC voltmeter readouts for those that want that feature. And these modules also have screw-terminal inputs and outputs so you don't have to fire up the soldering iron.
