Anyone know what that symbol on those (usually black) power blocks used for powering dvd's etc is mean to represent? It's a solid line above a dashed line. Looks like is AC AND DC (ho ho). Perhaps it means unsmoothed DC?
Electrical: dash over dotted line on those power block things
Jul 21, 2009
12 Replies
It just means DC, I don't think there is any implied level of smoothing.
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Just DC (DC is straight; AC is bent).
In particular, it does not include a voltage stabiliser, and on low loads the output voltage may considerably exceed that written on it. Devices that use the "solid/dash" bricks will include their own stabilisers if necessary. A few don't and require there to be a stabiliser in the brick (which is then marked with two solid lines). They may be destroyed if a "solid/dash" brick is connected, even if nominal voltage is "right". Small portable devices like digital cameras are common culprits, or rather victims :-( The built-in stabliisers are part of the reason that manufacturers' power bricks for cameras are relatively expensive.
Chris
1 out of 4 - ask electronics questions at your peril
NT
Rubbish. Stabilised supplies are marked with the solid line over a dashed line. I have at least two on my bench at the moment, both stabilised switch mode supplies.
More rubbish. They are expensive because they can be sold at that price to the general public who know no better. They may also use proprietary connectors or uncommon voltages, making it more difficult to substitute - even more opportunity to hike the price.
MBQ
Is wrong. The solid over dashed line is used for smooth regulated DC supplies as well as (or maybe rather than) "rectified AC". A switch mode laptop adapter being one case in popint, A 12V switch mode supply being another.
MBQ
Correct.
MBQ
Correct. See markings on page 36 of
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supplies, IEC 60417, No. 5031 Straight over dash line AC supplies, IEC 60417, No. 5032 Wavy line Mixed supplies, IEC 60417, No. 5033 Straight over wavy line
Ah, so that's what is meant by AC/DC - the third way.
They actually apply to the "mains" input side, but the symbols used for DC and AC output are the same. The output can't be mixed, it's one or the other.
MBQ
The solid line over the dashed line represents smoothed (but not necessarily regulated) d.c.
It is a representation of what you would see if you connected the supply to the input of an oscilloscope.
The dashed line represents the zero volts graticule line (i.e the horizontal centre line of the display with y-offset set to zero) and the solid line represents a positive d.c. voltage.
Similarly, the wavy line represents a sine wave, which is what you would see on an oscilloscope with an a.c. input. However, here the dashed line has been omitted as the wavy line is sufficiently iconic on its own.
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