Nope, you can buy them individually from Allied (I did that for some) or as many in a string as you want. And yes when I ordered 5 blue ones they were wired together but I can't say that's going to be the case all the time. The wires are fairly short when they cut a string but can easily be wired together. You might want to just order a few of various colors to see if they'll work as desired for your application. BTW, if you do order some pay attention to the shipping method for cost purposes. Some of the shipping options are kind of costly. Double backed tape for mounting under a cabinet would be ideal.
I had the same idea, but used LEDs. I used lengths of flat plastic conduit, with holes drilled at regular intervals for the LEDs. Two lengths of wire run parallel inside the conduit, each LED and resistor then soldered to these. The conduit is hidden completely by the moulding under the units, and it looks really nice when on. On reflection, "straw hat" LEDs would give a better spread of light, but it's quite nice as it is. Runs from a spare 12v PSU I had lying around, and cost buttons.
All Electronics which is one of my faviorite sources for odd parts and assemblies has been selling the CCFL lamps along with the inverters for a long time.
Here is the page for them.
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They also carry lots of Led stuff Too.
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You can find light strips in this listing that operate from 12 and 24 volts as well as a lot of other types.
they specalize in surplus and new parts of interest.
There are plenty of LED strips on that website and they also have flexible self adhesive LED 'tape' which you can cut to length (there is a minimum length multiple though). I've uses them quite a few times now, not the fastest if you choose the free shipping but they've never let me down yet.
Unfortunately 'white' LEDs do dim over time, the phosphors used emit less and light output goes down even when driven consistently at lower than maximum ratings. The cheaper the LED, the faster they dim and also the harder you drive them...
The main problem I had when they shipped requirng a signature. Next time post man left it, but I did complain to the company. Sometimes you will get back orders, and its confusing on the documents.
I use their 350 ma. drivers that work off AC or DC. Getting the right LED color is the main problems with lighting. The Cree I mentioned fills the bill for me.
I unplugged one LED from the string and used a 'scope to measure the voltage across the LED and a clip on 'scope current probe to measure the current.The string connection was somewhat obscure, and I did not trace it out, but the LEDs 'appear' to be in series. However, when I removed one it did not turn any others off. When I had removed the 24 that I needed for the digital display and then plugged the string in, none of the remaining 11 LEDs lit.
In my application in the digital display, there is a DC power bus of about 8V [bright] that feeds each LED through a resistor, and then an 'open collector' to common to switch the LEDs on or off. The light sensor varies the voltage on the power bus.
Clint Sharp's comment " Unfortunately 'white' LEDs do dim over time, the phosphors used emit less and light output goes down even when driven consistently at lower than maximum ratings. The cheaper the LED, the faster they dim and also the harder you drive them..." probably explains what is happening since these are likely very cheap LEDs.
Without the diffusers, these LEDs are semi-spot and at a range of about 40cm would give a softly defined light circle of about 20cm diameter. One LED does not throw a huge amount of light, but 35 of them do.
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