12 volts DC?

Your meter is calibrated for 'steady' DC as you would get from a battery or stabilsed supply.... It is unlikely that any of the above controllers supply pure DC, an unregulated rectified DC is typical, and meter being 'electronic' samples the waveform at intervals to derive a value...A mechanical movement will give a better idea of the voltage from these supplies, as it is not fast enough to follow the variations at 50HZ... Also any voltage you check on the output of these controllers should be 'under load', preferably a fixed resistor. The readings you quote have no meaning without looking at the waveform, and 'DC' stamped of the rating plate is rarely pure DC.....

In message , turbo writes

It was "under load": I omitted to mention that the train was running at the time the readings were taken.

Thanks for your reply, which makes sense. I'll try with the old "analogue" multimeter next time I'm in the garden.

A digital meter is absolutely useless on anything other than a constant stabilised voltage, you will get a far more accurate reading with a good analogue meter (i.e AVO or similar). The other thing is, are these all "No-Load" voltages ? because if they are, they will be significantly higher then when the output is "loaded"

Regards Keith

take a valium and calm down.

you must not put too much faith in labels. These are all reasonable approximations for the voltage given the application.

06 10 05 Hi Jane, I have just read your query regarding 12v DC etc. You mention DC from a Transformer -- now transformers supply only AC ( unless it is a transformer / Rectifier), in this case it will supply regulated or unregulated DC voltages. This is determined by the cost usually. in either case there is often a strong "ripple" of AC superimposed on the DC. This is ignored by a conventional small motor as the effect is reversed every 1/50th second (mains frequency). Modern digital voltmeters "see" these ripples and add them to the DC present. I don't trust them! Chips cannot amplify the voltage, the best that they can output is the max input & even that is unlikely (efficiencies etc). The output of a DCC system is a series of pulses in a time shared sequence. Each chip is set to decode only one of the sequences available from the controller. As far as the voltmeter is concerned this will be a form of AC and read it as such.The motor will however integrate the pulses and use them as DC. If the max pulse was say 12 volts and it was present for 1/8th of the time (8 locos could be controlled) then the mean DC value would be 12/8 = 1.5 volts. ergo to give a higher running voltage it requires a higher input voltage, rather like you have observed. in other words, your voltmeter is seeing the peak value and not the average value which the motor sees. I hope that this is not too verbose. Don't be afraid to ask if you have any questions. Yours Aye Peter Abraham Montarlot France