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| AlcidePiR2:
Dear All, I made a mistake. I desoldered these laser diode ( from a HP Laser printer board RM1-4756) before noting the pinout. In any case, this would not have been sufficient to identify the laser diode. Can any of you can help me on this ? - identification of the laser diodes ? - identification of the pinout ? And as well for the phototransistor photodiode ? written 9Z AL ?? Thanks |
| AlcidePiR2:
Really ? Nobody on this one ? I have searched on my side but I am quite frightened to see the variety of pinouts for laser diodes. I see also that many have reverse voltage limit of only 2 V, so I dont want to try too much randomly. Best Wishes to all. |
| NiHaoMike:
http://repairfaq.org/sam/laserdio.htm#diodct2 --- Quote --- After having played with several CD and CD/RW diodes, I believe that it is possible to determine the pinout to a high degree of confidence without applying any significant power to the laser diode. All that is needed is a voltmeter (rather a millivoltmeter) and an operating incandescent lamp (tungsten filament like a pocket flashlight). If you direct a light beam to the device under test and measure the voltage between common and each of the other two pins you will find two of the four following possibilities: About +500 mV. This is a PD anode. About -500 mV. This is a PD cathode. About +5 mV. This is a LD anode. About -5 mV. This is a LD cathode. The large difference is due to the fact that the photodiode is a much more efficient converter of light to electricity although both the PD and LD work as photo cells. The above figures depend on the intensity of the light but there will be no mistake: The PD voltage will always be much larger that the LD voltage. --- End quote --- |
| ChristofferB:
They have no markings at all? Why dont you look up one of the 4 driver ICs and use its pinout to find what connects to what? Alternatively make a current limited 2V supply and just try all combinations. (Without shooting your eye out!). Sacrifice one of the diodes. I'm not even sure it would damage it to be reverse connected briefly. |
| Gyro:
Note that bare Laser diodes like that are very ESD sensitive. You need to handle them with care. The 8 pin "photodiode" is actually an IC with active circuitry on it. It looks as if pin1+pin5 and Pin 3+6 are supply and ground (but not clear which polarity).. Pin 2 looks like the output, and pin 4 either a power-on reset or an internal bias supply (capacitor connected to supply or ground). |
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