Post by thread:[OT]: LCD

Hello All, What is the voltage needed for elecrto luminescient backlighting for an LCD? Thanks, Royce -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

On Thu, 3 Apr 2003 16:59:16 -0500, Royce Simmons wrote on [OT]: LCD: >Hello All, > >What is the voltage needed for elecrto luminescient backlighting for an LCD? This should be written on the data sheet; the ones I use (2x16) take 80mA at a maximum of 4 volts. I use PWM with a 2N2222 switching transistor up to a cycle rate of 85% to feed them from 5 volts (the transistor has a VCE sat of about .5 volts so I shoyld be safe at that rate). If you do not use PWM, then a 10 or 12 ohms resistor from +5V is necessary to drop about a volt at 80 mamps. * spam_OUTsoubieTakeThisOuTatlantic-line.fr * .....soubieKILLspam@spam@astrosurf.com * http://www.astrosurf.com/soubie * Alimentation thermostatée à découpage AlAudine NT: * http://www.astrosurf.com/soubie/alaudine.htm * Au royaume des aveugles, les borgnes sont mal vus... - P.Dac -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

At 04:59 PM 4/3/03 -0500, Royce Simmons wrote: >Hello All, > >What is the voltage needed for elecrto luminescient backlighting for an LCD? Check the spec sheet but typical values range from 85 Vac to 200 Vac at frequencies in the 100 to 400 Hz range. Brightness is directly proportional to voltage and frequency and the half-life of the EL panel is inversely proportional to brightness: the brighter the panel, the shorter the life. Do make sure that you have an EL back-light panel and not LEDs. They can give similar results but LED back-light panels need about 4V at about 60 or so mA (DC). dwayne -- Dwayne Reid <dwaynerKILLspamplanet.eon.net> Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 19 years of Engineering Innovation (1984 - 2003) .-. .-. .-. .-. .-. .-. .-. .-. .-. .- `-' `-' `-' `-' `-' `-' `-' `-' `-' Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Check the spec sheet but typical values range from 85 Vac to 200 Vac at frequencies in the 100 to 400 Hz range. My observation is that some EL devices specify voltages as Vp-p (ie designed to be used with inverters), and others as Vrms (ie designed to be used with wall-supplied AC.) These are very different from one another, so watch out! Your LCD backlight requirements will differ even MORE if the LCD has a built in inverter... BillW -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics