SLP Posted May 28, 2010 Report Share Posted May 28, 2010 hi folks, I'm about to build a bigger VU-meter using the LM3915. The IC has open collector outputs which can sink 30 mA max. I need 120mA per output. first Idea: 4009 inverting buffers (with pullup reistors) and some ULN2803 (or 2804) driver ICs. But I guess, that's pretty hardcore. second Idea: would a simple PNP-transistor per output work? Any Idea, which type would be suitable for 120mA@5V ? thanks in advance. Quote Link to comment Share on other sites More sharing options...
Janis1279 Posted June 24, 2010 Report Share Posted June 24, 2010 (edited) hi folks, I'm about to build a bigger VU-meter using the LM3915. The IC has open collector outputs which can sink 30 mA max. I need 120mA per output. first Idea: 4009 inverting buffers (with pullup reistors) and some ULN2803 (or 2804) driver ICs. But I guess, that's pretty hardcore. second Idea: would a simple PNP-transistor per output work? Any Idea, which type would be suitable for 120mA@5V ? thanks in advance. I prefer a PNP-transistor type BD136 or similar Regards, JanisBD136.pdf Edited June 24, 2010 by Janis1279 Quote Link to comment Share on other sites More sharing options...
TheAncientOne Posted July 11, 2010 Report Share Posted July 11, 2010 The LM 3915 outputs will drive solid state relays. We once built some 3 metre tall VU meters for a night club, using mains bulbs. Later version added lamp pre-heat, (basically a small dimmer feeding a little current into each lamp to warm the filaments, and reduce fatigue failure). On the same tack, using filament heating transformers, you can build 7 segment displays from fluorescent tubes. 4 metre high digital clock, anyone? Quote Link to comment Share on other sites More sharing options...
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