Re: HP 9821 - display and tape transport issues #VintageHPComputers


Using the old ldr isn't a good idea, the ldr will degrade more over time. At the best it will be a short time solution. I think the 5616 should work.


On Wed, Feb 19, 2020 at 8:04 PM +0100, <mariuszmleczko@...> wrote:

Code: GL5616D
Diameter: 5mm
Light resistance:       
- 10lx - 5÷150 kΩ
- 100lx - < 2 kΩ
Dark resistance: 1 MΩ
Power: 100mW
Maximum voltage: 150V DC
Wave length: 540nm
Working temperature: -30°C ÷ +70°C

Will that be OK ? I'm not sure which 10lx or 100lx value take into account for light resistance condition.

Do you you think is it good idea to do a testing of existing LDR by adding ~13K resistor to it ? In a dark condition it shall give more than 19k which is more than 18k barrier.

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