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Discussion Starter #1
You just put on the other forum.

We have looked for matching meters for years and I can’t find them over there.

Thanks so much.

Bill
 

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I’m wondering if I could use 2 of them with something like this for my 4 train loops and one streets loop. No specs are given for the rotary switch.

https://www.ebay.com/itm/Alpha-6-Position-2-Pole-Rotary-Switch-Break-Before-Make/162516850535?_trkparms=aid=555018&algo=PL.SIM&ao=2&asc=20160908110712&meid=51bb537916d441328bef0ab32170e163&pid=100677&rk=3&rkt=30&mehot=none&sd=162516850533&itm=162516850535&pmt=1&noa=0&pg=2386202&algv=SimplAMLv5PairwiseWeb&_trksid=p2386202.c100677.m4598

Never mind. After thinking about it, only the track being measured would get power thru the ammeter.
 

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So why are these set up to only used isolated power supplies? Glad this was mentioned on the other forum.
I mentioned it in my first post here as well. To power the electronics and allow low voltage/current measurements, they need external power. Obviously, that power can't be connected in any way to the measured power, so it has to be isolated. It's the same as your multi-meter, the batteries supply the isolated power.
 

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I mentioned it in my first post here as well. To power the electronics and allow low voltage/current measurements, they need external power. Obviously, that power can't be connected in any way to the measured power, so it has to be isolated. It's the same as your multi-meter, the batteries supply the isolated power.
So you can’t connect all, in my case two volt meters, and two amp meters to one Single external 5 volt supple. I had one pc supply in mind but have plenty of old cell chargers laying around.
 

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Nope, I'm pretty sure you'd release some magic smoke. They meters share circuit ground with the power being measured, so thinking about ammeters specifically, there's no way that could work. If the two voltages are from different sources, the same caution applies, you'd be tieing them together through the high impedance circuitry of the meter, when one of them was turned off or even lower/higher in voltage, the differential would surely toast the meter.
 

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Nope, I'm pretty sure you'd release some magic smoke. They meters share circuit ground with the power being measured, so thinking about ammeters specifically, there's no way that could work. If the two voltages are from different sources, the same caution applies, you'd be tieing them together through the high impedance circuitry of the meter, when one of them was turned off or even lower/higher in voltage, the differential would surely toast the meter.
That’s the explanation I needed. Each one will have a separate PS. On another note my expected delivery is late April :eek:
 

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That's why I like analog meters. No PS required to measure the power source. Of course, the analog meters are a better aesthetic fit for my prewar focus and conventional operation.

When measuring track voltage using a digital test meter the value jumps around as the train moves along the track (different current draw, imperfect connection between track and loco, back emf). That requires some concentration to ascertain a value.

With analog meters, the designs inherent damping serves to minimize that effect. And the visual needle intrinsically eases discerning a changing value. I presume the same effect would apply to amp meters.

Do the digital meters have any electronic damping of the displayed value? Would the analog AC volt meters inherently measure an AC rms voltage given a partial duty cycle waveform from modern transformers?
 

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A unit like this could ease PS and wiring proliferation. A single 5 V PS powering one of these isolated DC-DC converters at each digital meter. It's good for 200 ma output at 5 V.

DC.png
 

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A unit like this could ease PS and wiring proliferation. A single 5 V PS powering one of these isolated DC-DC converters at each digital meter. It's good for 200 ma output at 5 V.

View attachment 530140
Yeah saw those on the other forum. I’m going to experiment with these meters when they show up. Measure current draw from the supply. How accurate they measure, etc,etc. 5volt ac/dc adapters are 6 bucks on eBay. All depends if want ease installation or least expensive way of powering them up.
 

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Yeah saw those on the other forum. I’m going to experiment with these meters when they show up. Measure current draw from the supply. How accurate they measure, etc,etc. 5volt ac/dc adapters are 6 bucks on eBay. All depends if want ease installation or least expensive way of powering them up.
I get 1 amp AC to USB chargers at my local dollar store for, well a dollar.
 

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Looks like my meters has hit the states, so maybe I'll be testing them in a week or two. Still haven't decided how to power them. Many options, individual wall warts, isolated PS running off the transformer. I'll figure it out.
let us know as id definitely like to get a couple of those too!!!!
 

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Received my meters yesterday. I ordered two and they sent one that's wrong. A DC 10 amp meter instead of AC. I'm in contact with the seller. Shouldn't be a issue getting the correct one.

Anyway tested on the bench. Works very well. Calibration was a little off but there's an adjustment pot. The wiring/connector for the current you are measuring with is 24/26 awg. Contacts for the connector are also a weak point. No way this can handle 5, 6, 10 amps without issues down the road. So I un-soldered the connector and soldered in it's place 16 awg wire. Should mate well with the 14 awg bus wire I use under the layout. I'm doing a video of the operation. I'll post tonight.
 
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