18-04-2013, 08:48 AM
Its worth noting that on many LCD displays, the backlight is not LED - rather, the trend is to use electroluminescent (EL) sheeting as emission is even and distributed, rather than point source.
You can buy EL sheeting and wire in different colours - its fun to play with. Downside is that unlike LEDs which have a simple DC supply, EL requires an AC voltage (typically at a few kHz) of between 60 and 600V at a very small current - such inverters are now commonly available very cheaply (few quid) and extremely compact - often built into the LCD display panel. NOte that with such inverters, you need good screening to minimise the risk of interference with radio and audio devices...
Cheaper LCD displays therefore tend to use LEDs, more whizzo ones use EL backlighting with a correspondingly (slightly) higher price.
Search eBay for "el sheet" and "el inverter" for loads of hits...
PS. General point about these cheap meters - they are incredibly easily confused by RFI - they completely lose the plot - I've had this when driving class-E plasma speakers etc. Any semblance of accuracy in the readings goes completely out the windows - both volts and amps can be 50 or 100% out...
You can buy EL sheeting and wire in different colours - its fun to play with. Downside is that unlike LEDs which have a simple DC supply, EL requires an AC voltage (typically at a few kHz) of between 60 and 600V at a very small current - such inverters are now commonly available very cheaply (few quid) and extremely compact - often built into the LCD display panel. NOte that with such inverters, you need good screening to minimise the risk of interference with radio and audio devices...
Cheaper LCD displays therefore tend to use LEDs, more whizzo ones use EL backlighting with a correspondingly (slightly) higher price.
Search eBay for "el sheet" and "el inverter" for loads of hits...
PS. General point about these cheap meters - they are incredibly easily confused by RFI - they completely lose the plot - I've had this when driving class-E plasma speakers etc. Any semblance of accuracy in the readings goes completely out the windows - both volts and amps can be 50 or 100% out...
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