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dogshed
Joined: 28 Apr 2006
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 Posted: Thu Aug 24, 2006 10:32 am Post subject: voltage converter not for electronics? |
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My voltage converter says not for use with electronics. Why would they say this? I thought it was just a transformer and a fuse.
My laptop might pull more watts than a hair drier but my battery charger?
-Jeff |
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ttompatz
Joined: 05 Sep 2005
Location: Kwangju, South Korea
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| Posted: Thu Aug 24, 2006 2:57 pm Post subject: Re: voltage converter not for electronics? |
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| dogshed wrote: |
My voltage converter says not for use with electronics. Why would they say this? I thought it was just a transformer and a fuse.
My laptop might pull more watts than a hair drier but my battery charger?
-Jeff |
Changes in the sine wave of the output from the transformer may cause problems with some electronics.
Having said that, most modern electronics have chargers / power bricks that are adaptable from 110-240v and 50-60Hz. Check to see if you need a converter first.
PS. your laptop will NOT use as much as a 1500w hairdryer. Most computers run on 300-500 watts (1/5 - 1/3 as much as a hairdryer). |
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keninseoul
Joined: 09 Mar 2004
Location: Seoul
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| Posted: Fri Aug 25, 2006 6:23 pm Post subject: Sine Wave??? |
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| Quote: |
| Changes in the sine wave of the output from the transformer may cause problems with some electronics. |
Just what are we talking about here?
One of those cheap small travel voltage 'converters'? No transformer in them - just a diode that lops off half of the sine wave to reduce the voltage from 220 to 110v
Or an inverter? They commonly produce a square wave or triangle wave.
An inverter converts (usually) 12V DC to AC.
A step-down transformer just makes the sine wave input smaller - no change to the sine wave.
An AVR (automatic voltage regulator) often has a step-down output - tapped off the transformer. Usually uses a set of relays to maintain the output voltage. No changes to the sine-wave.
It might be just a paranoid disclaimer - nearly all electronics have no problem with minor differences in voltage, frequency, and wave-form shape (sine wave, pseudo sine waves). Square and triangle waves might well give some senstive electronics (like PCs) a problem. |
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dogshed
Joined: 28 Apr 2006
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| Posted: Wed Aug 30, 2006 1:14 pm Post subject: Re: Sine Wave??? |
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| keninseoul wrote: |
| Quote: |
| Changes in the sine wave of the output from the transformer may cause problems with some electronics. |
Just what are we talking about here?
One of those cheap small travel voltage 'converters'? No transformer in them - just a diode that lops off half of the sine wave to reduce the voltage from 220 to 110v
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I just assumed it was a transformer. From what I remember about electronics a diode used to lob off half of the sine wave still have the same voltage but would be a pulse. Using a zener diode, which has the power go through "backwards" would reduce the voltage but produce heat. The converters for your car that drop the 12VDC to 9 or 6 VDC use a zener diode.
I'm not sure how pulsed power would effect a NiMH battery charger.
-Jeff |
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keninseoul
Joined: 09 Mar 2004
Location: Seoul
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| Posted: Fri Sep 01, 2006 5:59 pm Post subject: diodes & zener diodes |
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| Quote: |
| a diode used to lob off half of the sine wave still have the same voltage but would be a pulse. Using a zener diode, which has the power go through "backwards" would reduce the voltage but produce heat. |
diodes
if half the sine wave is gone, how can the voltage be the same??? it is cut in half. diodes do not affect current per se, in case you thinking about Watts
zeners
not backwards - but the idea isnt far wrong; the zener 'breaks' down if the forward voltage exceeds its zener voltage, and only passes that voltage, so if you pass 12volts across a 6v zener, you get 6volts out.
heat
"everything" produces heat. even regular diodes (there is a 0.6 or so voltage loss across [silicon] diodes - pass enough current and yes you can substantial heat even in a diode.
yes, you can get 6v from a 12v supply using a
zener (and resistor) - low to medium power
series of regular diodes - med to high power
resistor divider - low to medium power
transistor and any of the above - med to high power |
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keninseoul
Joined: 09 Mar 2004
Location: Seoul
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| Posted: Fri Sep 01, 2006 6:12 pm Post subject: affect |
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| Quote: |
I just assumed it was a transformer.
I'm not sure how pulsed power would effect a NiMH battery charger. |
You can get some idea if a transformer is there by the weight and size. if it has some weight & bulk then its more likely there's a transformer lurking inside
A GOOD NiMH battery charger uses some advanced electronics - I would not recommend feeding it 'pulsed' power |
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dogshed
Joined: 28 Apr 2006
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| Posted: Fri Sep 01, 2006 6:37 pm Post subject: Re: diodes & zener diodes |
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| keninseoul wrote: |
| Quote: |
| a diode used to lob off half of the sine wave still have the same voltage but would be a pulse. Using a zener diode, which has the power go through "backwards" would reduce the voltage but produce heat. |
diodes
if half the sine wave is gone, how can the voltage be the same??? it is cut in half. diodes do not affect current per se, in case you thinking about Watts
zeners
not backwards - but the idea isnt far wrong; the zener 'breaks' down if the forward voltage exceeds its zener voltage, and only passes that voltage, so if you pass 12volts across a 6v zener, you get 6volts out.
heat
"everything" produces heat. even regular diodes (there is a 0.6 or so voltage loss across [silicon] diodes - pass enough current and yes you can substantial heat even in a diode.
yes, you can get 6v from a 12v supply using a
zener (and resistor) - low to medium power
series of regular diodes - med to high power
resistor divider - low to medium power
transistor and any of the above - med to high power |
Either you are wrong or you are not good at explaining things.
When a zener diode is used for voltage regulation the current is "reversed biased" compared to a regular diode.
http://en.wikipedia.org/wiki/Image:Rectified_waves.png shows some wave forms. The pulsed rectified graph in the middle of the first figure shows the same voltage as the AC wave. Voltage is measured from the zero point in the middle. If you have a single phase source and a single regular diode (not zener) then you get a pulse with the same voltage as the AC source.
Even a four diode rectifier gives you pulsed DC. Another poster pointed out that that is probably the issue. |
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dogshed
Joined: 28 Apr 2006
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| Posted: Fri Sep 01, 2006 8:37 pm Post subject: |
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I'm thinking peak and you are thinking average maybe?
Maybe there's a capacitor that turns that pulsed into something else.
I'm moving now and not sure where that converter is. Maybe I'll open it up and see what's inside. For my laptop I just need the little plug adaptors that came with it.
-Jeff |
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