Three-in-one-power... this right/safe???

[niftydog]

Lets say the LED needs 25 mA to be happy. If the pedal needs 5 then how can the LED light? I can see where the resistor will keep the LED protected if the pedal is drawing 100mA.

the LED and it's resistor are in parallel with the pedal. The voltage across both always remains the same, thanks to the regulator. Ohms law tells us the current is dependent on voltage and resistance. Since the voltage across the LED/Resistor is constant, and the LED resistor is also constant, the current through that branch must remain constant also.

If the LED were wired in series with the pedal, then it would be a different story. I believe this is where your confusion lies.

the switch may short hot to neutral. Un-fun.

I would think, although it's only a gut feeling, that a mains power rated DPDT switch would be designed so as to avoid this scenario. The individual poles of the switch should be mechanically separated from each other or else you risk arcing etc.

Even so, the worst that should happen is that the circuit breaker will trip.

The alternative is far more dangerous. Often the active and neutral wires are mistakenly interchanged. If this is the case, and your device only switches the supposed "active", then there's a chance that the real active is permanently wired to the circuit, even when the switch is off.

in the UK our AC supply at 220V is a lot more dangerous

that's contentious. Current kills, not voltage, and the yanks have twice as much current on tap as you or I (Australia) but we all have much the same power available. We digress...

[ethrbunny]

My bad. I misread the diagram. I was hoping the LEDs were going to light when something was plugged in. As it stands now they indicate that the regulators are working.. right? Thats why I was thinking the circuits were in series.

D'oh!

[davebungo]

in the UK our AC supply at 220V is a lot more dangerous

that's contentious. Current kills, not voltage, and the yanks have twice as much current on tap as you or I (Australia) but we all have much the same power available. We digress...

It takes only a matter of 10's of milliamps for a short period to kill so the difference between current availablity on the mains supply in the UK/US/AUS has very little to do with the argument.

OK A 12V car battery supply across a metal watch strap will do a lot of damage due to heat but ohms law states that 220VAC across a human being will induce about twice as much current as 110VAC in simple terms so don't go telling me that it's contentious - it's not.  Let's have a vote and see how may people would opt to put their hands across 220VAC rather than 110VAC.  This is one of the reasons for using 110V instead of 220V.  Building sites in the UK use 115VAC transformers for power tools for much the same reason.

[niftydog]

jebus! Take a chill-pill dude. You took that very personally.

I was trying to express (perhaps not very successfully) that it's not in anyones best interest to decide which is more dangerous; that is irrelevant. Suffice to say they are both potentially deadly and leave it at that.

don't go telling me that it's contentious

Hark, true irony! Take note Alanis!

If it's NOT contentious, then why are we debating it? (rhetorical question alert!)


peace and love,  

your Safety-Nazi

[NaBo]

hmmmmmmm...  :?

I think i'll just stick with R.G. on this one.  I've said something quite similar to this on a few occasions, but if switching both AC power lines is good enough for him (not to mention Paul M.), it's good enough for me- that guy seriously knows his stuff.  :wink:

[davebungo]

jebus! Take a chill-pill dude. You took that very personally.

I was trying to express (perhaps not very successfully) that it's not in anyones best interest to decide which is more dangerous; that is irrelevant. Suffice to say they are both potentially deadly and leave it at that.

don't go telling me that it's contentious

Hark, true irony! Take note Alanis!

If it's NOT contentious, then why are we debating it? (rhetorical question alert!)


peace and love,  

your Safety-Nazi

Well, (sorry) I probably did come across quite abrasively and I didn't realise I was capable of such irony - I'm from the North, you will have to excuse the directness in my point of view (which I stand by completely).

[niftydog]

hey, don't be sorry, we both have the right to stand by our opinions. No offence taken - I just went a bit looney because I hate when this place gets bogged down in silly arguements.

[davebungo]

Well at least we've been introduced now.