Re: LED activated by LDR

HEMOglobina wrote:

Let's say I have a circuit like this:

http://img504.imageshack.us/i/ldr.png/

When I shine the LDR, the LED instead of having only 2 states (on or
off), it lights up kind of proportonally to the amount of light I put
on the LDR (from weak to fully lit). I know this is how the transistor
works, but What can I do to make the LED either light up fully or not?
I know I could use a relay (to act as a switch), but I'm pretty sure
that would be overkill. Is there another component or circuit
configuration that I could use?
As you might have guessed I'm pretty newbie in electronics.

Thank you for your help,
HEMOglobina
You need a hysteresis circuit..

that would be a comparator type circuit with a (+)
feed back to slightly offset the trigger point of the
(-) input when switched.


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