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How to turn on the backlight of this LCD?

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ericmar

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hi,

Has anyone used this LCD before? There are only 14 pins so how do I connect the A or K to turn on its backlight?

**broken link removed**

Thanks for any help!

Regards,
Eric
 

Look carefully at page 2 of the datasheet you list in your message. There is a mechanical drawing of the LCD module that shows the "A" and "K" (anode and cathode) pads for the backlight LED power on the right hand side of the display module. The 14 pins that connect the data lines are a separate connector on the left hand side.
 

For an 'EL' backlight, you usually need an inverter circuit. This will provide voltage in the order of 100~200V 400Hz sinusoidal waveform.

Those modules can be found as an integrated module, which you simply connect 5V or 12V input at one pin, and output the required waveform at a second pin, with a common GND.

Those can be found an places like DigiKey, or other supplier. Just make sure you get a module that can drive the desired area. Usually, you measure the viewing area in cm^2 or inches^2, and the EL inverter need to be rated for at least that area.
 

"Big Boy" is absolutely correct regarding EL backlights.

Your module comes in three different versions - EL backlight, LED backlight, or no backlight. You need to find out which type you have, then power the backlight accordingly.

An LED backlight will only require a current limiting resistor in series with the DC power supply.

An EL backlight will require some higher AC voltage; HOWEVER, you should not make any assumptions about what voltage is required. EL backlights can require any voltage from tens of volts to several hundred volts depending on the type, thickness, and size. You will need data from the manufacturer regarding the required voltage and recommended frequency.

You may want to call Jaycar or Electus Distribution to see what they can tell you about the product.
 

Well, I got a dot-matrix LCD one day. This is a surplus component that was used at my former company in their system, and was probably custom-made. Anyhow, I wasn't able to find any information on that module itself so I reverse-engineered the pinout, by tracing to the chips on the module (which chips were well-documented). The module also had a short RCA cable, so I figured that this was EL backlight. I just went to digikey website and ordered an EL inverted. This was the biggest of their inverter, which was just enough for the LCD size. The module was a simple cube of about one inch square per 3/4 inch heigh, with 4 pins (1 5V input, 1 output, and 2 common ground pins).

I used this inverter and it worked like a charm. EL backlight give a soft blue light. By changing the input voltage, the backlight got brighter or darker, so you can somehow adjust the contrast this way.
 

House_Cat said:
"Big Boy" is absolutely correct regarding EL backlights.

Your module comes in three different versions - EL backlight, LED backlight, or no backlight. You need to find out which type you have, then power the backlight accordingly.

An LED backlight will only require a current limiting resistor in series with the DC power supply.

An EL backlight will require some higher AC voltage; HOWEVER, you should not make any assumptions about what voltage is required. EL backlights can require any voltage from tens of volts to several hundred volts depending on the type, thickness, and size. You will need data from the manufacturer regarding the required voltage and recommended frequency.

You may want to call Jaycar or Electus Distribution to see what they can tell you about the product.
I think the one I have now is with EL backlight. Is it true that I'll need to supply AC voltage in order to turn it on? I tried +5V but it doesnt work!

Thanks!
 

Yes, you will need a higher voltage AC to run an EL panel. The links below will give you some material to read that will help you understand what is necessary.

**broken link removed**

**broken link removed**

**broken link removed**
 

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