> assuming 16 volts RMS from the transformer, a single anti-parallel diode pair, and a .65 forward-voltage drop: The RMS voltage to the locomotive is 15.42, that is, a drop of .58 volt. A simple rectifying meter would read 15.28, an apparent drop of .72 volt.
Am I correct that a "simple recifying meter"** is more or less the same thing as a "cheap multimeter"? If that's the case then my cheap VOM will be displaying a lower voltage downstream of my diode pairs than the actual RMS voltage and consequently the voltage drop for each diode pair is actually less than the 0.3 volts I mentioned in my original post.
I'm either misunderstanding something you said or I must have gotten the wrong type of diodes (something with a forward voltage drop much lower than 0.65v). The other ones I got that were Shottky diodes measure a drop of 0.1v per pair. I had no idea...thought that was a brand name. I have since learned they are made with a different material. Fortunately I've bought small quantities since I figured there would be a learning curve. My experimenting thus far has cost less than a couple of sections of Gargraves track.
> By the way, there istive to individual diodes.
Yes, I've read your (and others') posts about that on the forum. It seemed to me that the price of a bunch of 4-diode modules would be much greater than the price of 4 times that many diodes plus the terminal blocks to hook them together. Seems like I need to do more research.
Where do you buy diodes (or bridge-rectifier modules) when you need them? Since Radio Shack more or less cratered I don't know of any local electronics parts stores. What specs should I look for - amps, volts, etc? (One of my transformers is a ZW, so 20v max.) Is the forward-voltage drop of a diode always called that or is some other nomenclature used by different manufacturers.
**I Googled "rectifying meter" and if I understood it correcly it seems to be what you described in your last paragraph: In order to make it possible for a multimeter to measure AC & DC with a single (DC) meter a full-wave recifying bridge is added to the AC measuring function to convert te AC to DC which is then displayed as AC voltage on the meter. And it concludes with this statement: "The AC voltmeter produces an output voltage, which is equal to 0.9 times the rms value of the sinusoidal (AC) input voltage signal." Which is what you say in your last paragraph.
Thank you so much for helping me with my rookie questions. Last time I used my trains it was: set them up, put a lockon or two in each block, make sure the transformers are in-phase (I have taken note of your serious cautions on that), set up a couple 153C (?) controllers to keep the trains from hitttng each other and let 'em go. Can't believe how much good info is available on the forum.