Electronics

JS · Guest

This device which you insert between the lampholder and bulb,
switches the bulb on & off at random when it gets dark.

http://www.timeguard.com/details.php?product=34

I guess the device must contain some basic electronics.

------------

The full instructions says not to use this in a circuit which
contains a dimmer but why is this?

(1) Would the problem be that the dimmer and/or this device get
damaged?

(2) Alternatively, would the problem be simply be that the unit does
not function properly when the voltage (er, current?) is reduced by
the dimmer.

Victor Roberts · Guest

2 for certain and probably also 1.

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.

This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.

Palindr☻me · Guest

A dimmer basically chops out bigger and bigger pieces of
the mains sine wave input as it is turned down. Eventually
there is hardly anything of the sine wave left to power
either a lamp, or this unit.

Apart from anything else, the very simple means *normally*
used inside the unit to reduce mains voltage to the low
voltage needed for the unit's electronics won't produce
enough output to be reliable at lower dimmer setting.

I would be surprised if a simple dimmer were damaged by this.

The unit probably won't get damaged either but would simply
not work at all or be very unreliable at different dimmer
settings. But it is not using it as the designer intended,
so, it could.

Operating this unit with a circuit fitted with a simple (eg
rotary knob type) dimmer would probably be fine, if the
dimmer was always set to maximum, or very near maximum.

However, using it with a more advanced dimmer (e.g.
soft-start, remote control, etc) could easily cause
problems. These typically don't allow you to set the output
to maximum at all times.

However, it is never a good idea to operate anything other
than in accordance with the manufacturer's recommendations.
This is particularly a bad idea when having to make
assumptions about the design - as in this case.

--
Sue

Ian Stirling · Guest

RJTech · Joined: 24 Dec 2005 Posts: 2 Location: PA

Yes I'll have to agree with everything said. The device expect X amount current and gets > X . I can see how that would cause problems... but perhaps not damage.
_________________
In the end, it doesn't even matter...but when is the end?

neon · Joined: 25 Feb 2006 Posts: 580

Usualy a dimmer does not chop anything at all it just can't do that.The chopping refers to the actual rapresentation on a scope as AC being chopped. A dimmer simply delay the firing of a TRIAC SCR or other devices in such a maner as to provide conduction angles or power decrement as a result. Inside that device is probably a timer of sort that operate that unit at ramdom. As far damage to the unit the company concerne is that a dimmer can and will conduct during peak power as opposed to gradual turn on as with AC.

	Electronics Forum Index -> Components	All times are GMT
Page 1 of 1