flockandroll

Thanks, but that is not the solution for me...

Thanks. Thanks the 100 ohm variable resistor I have is 5W so not quite up to the job. I guess the bigger power supply will be easier.

I have a 100 ohm variable resistor, could I use that and an ammeter to check the current is under 3A ? Hopefully the heater will still put out enough heat!

50W with 12V would be 4.17A R =V/I so R = 12/4.17 =2.88 ohms But I need to be a little under 3A, so total R = 12/just less than 3 = just over 4 ohms, so I would need to add a resistor of about 1.25 to 1.5 ohms in series with the water heater. Is any of that correct? I can't remember what resistors I have...

I did wonder, but is it really that simple? And what would the maths be?

Thanks. So I guess I need to upgrade my power supply. Mathematically 12A 5A 60W should be sufficient. Will it be sufficient in practice? https://www.amazon.co.uk/COLM-Adapter-100-240v-Switching-Adaptor-12V-5A/dp/B07HRLGV3S/ref=pd_lpo_sccl_3/261-2754844-5307136?pd_rd_w=TiIAQ&content-id=amzn1.sym.448aab69-6fff-42b9-9d7a-f6325052a6f6&pf_rd_p=448aab69-6fff-42b9-9d7a-f6325052a6f6&pf_rd_r=2KTQJSYVF2SR9F4FEBYX&pd_rd_wg=p3WPg&pd_rd_r=14150e46-7d8e-48c1-8fb9-7a28f44b9e0a&pd_rd_i=B07HRLGV3S&th=1 The next one up is 12V 10A 120W, which seems rather a lot of power! https://www.amazon.co.uk/COLM-Switching-100-240v-Transformers-Accessories-12V-10A/dp/B07J43TMYW/ref=pd_ci_mcx_pspc_dp_d_2_t_1?pd_rd_w=8VGBm&content-id=amzn1.sym.8db49f41-2d78-4c1c-bc3b-fb9e44b9efb4&pf_rd_p=8db49f41-2d78-4c1c-bc3b-fb9e44b9efb4&pf_rd_r=2W566NZ5ERGF892C0ARD&pd_rd_wg=H7Ki9&pd_rd_r=c2f02bc8-f47f-4ec9-af30-29f421ae9698&pd_rd_i=B07J43TMYW Both come with a nifty adapter at the DC end so you can easily connect + and - wires, and I would hope to get some modelling use out of it at some time. So really, I just want to make certain in the real world 12V 5A 60W DC supply will be ok for the 12V 50W heater (it's 20% extra so it must be?). Thanks

I need to do a science experiment like this: Measuring the temperature of melting ice experiment - Temperature changes and energy - Edexcel - GCSE Physics (Single Science) Revision - Edexcel - BBC Bitesize https://www.bbc.co.uk/bitesize/guides/zpjpgdm/revision/8 I have a 12V power Supply that is rated at 3 amps. I have a miniature water immersion heater that is “12V, 50W”. In terms of current, voltage and power, can I safely use the power supply to power the heater? (In terms of wires and connections it is fine.) When I was much younger, I used to think that somehow, “Oh no, 50W at 12V, it will draw over 4 amps to get that 50W at 12 volts, so something will overheat and go pop or worse”. But now I also think, “There’s only a maximum of 3 amps available, and the heater won’t be able to magically get more than 3 amps, so all that will happen is the heater will run with only 36W, so it will not get as hot, but everything will be safe, and nothing will break” Which view is correct? The circuit will look something like this: Thanks!

http://Look North (East Yorkshire and Lincolnshire), Evening News: 16/01/2024: www.bbc.co.uk/iplayer/episode/m001vgx8 via @bbciplayer from 24.05

Tonight's BBC Look North for East Yorkshire and Lincolnshire, report on Market Deepening Model Railway Club about it's many youngsters. BUT begins by saying how the hobby is getting older and at risk of dying out (IIRC)! Look North (East Yorkshire and Lincolnshire), Evening News: 16/01/2024: www.bbc.co.uk/iplayer/episode/m001vgx8 via @bbciplayer from 24.05

Feeling a bit more confident with it now. Thanks all

So this way does actually change CV1 but "at arm's length" as it were, without using the "nuts and bolts" method of actually going into each CV as it were? And having to alter CVs to enable long addresses?

So going back to the locomotives that have CV1 = 3, I can do that for all of them, they will respond individually to themselves (if that makes sense?)?

Like this...ah!

So I have the knowledge to change CV1 to a short address, and the knowledge to rename the loco in the app. Not sure if it will continue to irritate me that for instance CV1 = 66 and the name is 667, and CV1 = 78 and the name is 7818

Indeed! So I have one loco that used to be CV1 set to 3, but I changed it to 37, two locomotives that have CV1 set to 3, and a fourth one that I expect also has CV1 set as 3. Having one of these CV1 = 3 locomotives on the track, I can control it with the Z21 app using the pre-installed loco 3 (see, I previously changed the name to Alex) So, one question is, if I put two locomotives on the track each with CV1 = 3 can I control them independently, or will they both respond ? I would have said that they will both respond, but now I am not so sure... (Should I re-title this thread as "Understanding and using Z21 black and loco addresses - a basic introduction"?)