"Arfa Daily" wrote in message
...

"Mark D. Zacharias" wrote in message
...

I just had a quick look at a few scrap lasers which were hanging around
the
workshop, and they have six connections to the

***** laser diode unit. *****

Looking
at a few schematics, these are one each for the anodes and cathodes of
the laser diodes ( one red, and one infra red for DVD and CD
respectively ) and one each for the feedback photo diode integrated with
each laser diode. The
snip

Just to be clear, I was referring to just the laser diode itself, not the
entire pickup.

Mark Z,

I do know the difference between a laser diode and an entire pickup, so I
was also referring to the laser diode, as I thought that I had carefully
explained, when I said that a typical one, used in a DVD player pickup,
has 6 connections, as opposed to one used in a CD only pickup, which has
only 3 connections. A complete pickup, either CD or DVD, has many more
connections, than 6.

A CD laser diode has two components in it - a laser diode and a feedback
diode, both integrated onto the same chip. A DVD laser diode, has the same
thing, but times two.

Arfa


P.S.

I have a Panasonic DVD pickup at work which is disassembled to show to
customers. The actual diode is plainly visible, and has 3 legs soldered to a
small flex PC board.

Mark Z.