Article View: sci.electronics
Article #8529Light Dimmer
From: Steffen Lindner
Date: Fri, 23 Nov 1990 17:11
Date: Fri, 23 Nov 1990 17:11
29 lines
1621 bytes
1621 bytes
I would appreciate it if any of you could help me with the following: Background Information: I am trying to built a digitally controlled light dimmer. This system should control about 24 individual channels. Each channel consists of one or more lights (incandescent). The maximum load on each channel is about 3A. The dimmer must allow a minimum of 16 brightness settings (more would be better). The system uses a microcontroller for I/O and triggering the TRIACs. All seems well except that I have not been able to come up with a simple, cost effective solution to reduce (eliminate) noise. Problem: A regular dimmer setup (controlling the phase angle of a TRIAC) produces substantial current spikes, since the load current is turned on under non-cross-over conditions. This causes a lot of interference. Another solution would be to always switch at cross-over points and just skip one or more half cycle. This works well as long as not too many cycles are skipped. At 1/16 of full brightness there would be a substantial flicker noticable. Are there any better methods of building a dimmer? Is there any way to trigger the TRIAC "gently" (ie. soft start)? Please help, Steffen
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arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!wuarchive!sdd.hp.com!hplabs!hpfcso!hppad!lindnerShow Full Headers
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!wuarchive!sdd.hp.com!hplabs!hpfcso!hppad!lindner From: lindner@hppad.HP.COM (Steffen Lindner) Newsgroups: sci.electronics Subject: Light Dimmer Message-ID: <2570007@hppad.HP.COM> Date: 23 Nov 90 17:11:21 GMT Organization: HP Panacom Automation Div Waterloo, Ont. Lines: 29