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why is the US not Metric
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Simon:

--- Quote from: VK3DRB on October 26, 2019, 02:14:27 am ---
--- Quote from: jonovid on October 25, 2019, 10:24:21 am ---here in Australia everything is Metric,  like most of the world.

--- End quote ---

WRONG.

Most engineers in Australia, including me, still use the term "0402", "0603", "0805" etc for surface mount resistor sized. There is some crossover in name sizes between imperial and metric which just adds confusion. But I can live with this.
 
But what is really annoying is engineers in Australia who use an imperial grid for schematic symbol grid lines in Altium. So when my schematic symbols have a 2.50mm grid pattern and I have to use them to modify some imperialist's 0.1" grid, the bloody pins don't line up.

Australians should abandon the antiquated imperial measurements once and for all. And use kPa rather that PSI.

I think the only countries that have not moved to metric are Liberia, Burma and, you guessed it... the USA :scared:



--- End quote ---

Yea I did the same. Really bad idea. Stick with 2.54mm. I actually went for 3mm to make the divisions make more sense and because if you want to drow nice detailed symbols you want a 1/10 resolution but CS would not do 0.25mm, it had to be over 0.254mm. So I went for 3mm grid and regreted it. I now use KiCad and just stick with their standart 0.1" or 2.54mm. I can live with that.
Simon:

--- Quote from: vad on October 26, 2019, 03:05:58 am ---
--- Quote from: VK3DRB on October 26, 2019, 02:14:27 am ---
--- Quote from: jonovid on October 25, 2019, 10:24:21 am ---here in Australia everything is Metric,  like most of the world.

--- End quote ---

WRONG.

Most engineers in Australia, including me, still use the term "0402", "0603", "0805" etc for surface mount resistor sized. There is some crossover in name sizes between imperial and metric which just adds confusion. But I can live with this.
 
But what is really annoying is engineers in Australia who use an imperial grid for schematic symbol grid lines in Altium. So when my schematic symbols have a 2.50mm grid pattern and I have to use them to modify some imperialist's 0.1" grid, the bloody pins don't line up.

Australians should abandon the antiquated imperial measurements once and for all. And use kPa rather that PSI.

I think the only countries that have not moved to metric are Liberia, Burma and, you guessed it... the USA :scared:

--- End quote ---
At least we drive on the right side of the road, unlike people of Botswana and Bangladesh.

--- End quote ---

Don't forget:

<iframe width="560" height="315" src="https://www.youtube.com/embed/BYeMotNIIGs?start=81" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
syau:
In commerical aviation (ie Boeing & Airbus) all tooling are in imperial unit but all measurement in Airbus is metric  :-DD

The worst thing is the wire gauge size AWG vs mm, due to slightly different in diameter, 2 set of wire stripper is required |O
mariush:
I agree with low voltage, but I'd go with 24v or 48v DC

24v is low enough to allow cheaper switching regulator ICs that work at higher frequencies allowing for smaller inductors and capacitors. 48v would mean less current, so thinner wires to each led bulb or to devices.

No conversion at the house panel would be needed, you could still have 110v or 230v for your big appliances. You could have a small 24v ac-dc converter on top ceiling or hidden in the lamp somewhere, or hidden in the fake wall by the power switch on your wall. 

Internal dc-dc converters inside the led lamps would be more efficient than AC-DC (especially those capacitor dropper psus) and they'd be able to do brightness adjustment more easily and with less flicker ...

You could also have some 24v..48v DC outlets ... imagine you have your laptop that has a 18.5v DC charger ... usb power delivery allows up to 20v , so you could have the laptop powered using a small 24v..48v ->20v usb power delivery charger.
We're using more and more super efficient laptops and tablets that work with 10-20w and charge within hours, so maybe you don't need 65-90w adapters with lots of mains filtering in them

Small wallwarts for 5v / 9v / 12v for various devices would also be more efficient and smaller and cheaper to make,  powering off individual outlets in an automated way would also be easier and cheaper (not having to deal with AC high voltage relays and all that)
 
 Also less worry about people using shit chargers with shit isolation on the transformers inside, and people dying from using such chargers in bathrooms, or wallwart blowing up due to shorted transformers
Less zapping yourself due to those Y capacitors between primary and secondary , less radiated noise etc etc..

You may not even have to hide these AC-DC converters in the walls ... you could have extension cords, power strips with built in 110v->24v..48v DC ... ex.. sell a power strip with 5 outlets and 250-500w (ex 24v..48v 10A)

We may be getting there with usb power delivery if 20v becomes more popular... we have already chargers with multiple usb ports which can do 65-100w on the ports.
vad:

--- Quote from: mariush on October 26, 2019, 01:17:18 pm ---I agree with low voltage, but I'd go with 24v or 48v DC

24v is low enough to allow cheaper switching regulator ICs that work at higher frequencies allowing for smaller inductors and capacitors. 48v would mean less current, so thinner wires to each led bulb or to devices.

No conversion at the house panel would be needed, you could still have 110v or 230v for your big appliances. You could have a small 24v ac-dc converter on top ceiling or hidden in the lamp somewhere, or hidden in the fake wall by the power switch on your wall. 

Internal dc-dc converters inside the led lamps would be more efficient than AC-DC (especially those capacitor dropper psus) and they'd be able to do brightness adjustment more easily and with less flicker ...

You could also have some 24v..48v DC outlets ... imagine you have your laptop that has a 18.5v DC charger ... usb power delivery allows up to 20v , so you could have the laptop powered using a small 24v..48v ->20v usb power delivery charger.
We're using more and more super efficient laptops and tablets that work with 10-20w and charge within hours, so maybe you don't need 65-90w adapters with lots of mains filtering in them

Small wallwarts for 5v / 9v / 12v for various devices would also be more efficient and smaller and cheaper to make,  powering off individual outlets in an automated way would also be easier and cheaper (not having to deal with AC high voltage relays and all that)
 
 Also less worry about people using shit chargers with shit isolation on the transformers inside, and people dying from using such chargers in bathrooms, or wallwart blowing up due to shorted transformers
Less zapping yourself due to those Y capacitors between primary and secondary , less radiated noise etc etc..

You may not even have to hide these AC-DC converters in the walls ... you could have extension cords, power strips with built in 110v->24v..48v DC ... ex.. sell a power strip with 5 outlets and 250-500w (ex 24v..48v 10A)

We may be getting there with usb power delivery if 20v becomes more popular... we have already chargers with multiple usb ports which can do 65-100w on the ports.

--- End quote ---
I totally agree. The example of 12VDC / 10A that I gave was a marginal case, just to show feasibility even at such low voltage. Higher DC voltages (24...48V) can deliver greater power and would be less expensive both in installations and material costs. 12-14AWG that is commonly used for residential wiring is 2-3 times less expensive than 10AWG needed for 12V / 120W, and is easier to work with.
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