analog vs digital potentiometers

sarathssca

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Jul 31, 2014
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chennai, india
Hello,

Just curious to know how does normal analog potentiometers compare with i2c controlled digital potentiometers like DS1807 and compare with LED-LDR setup for volume control ?

For LED-LDR setup do we need to use optocoupler or can we use normal led and ldr and tape them together as shown in few threads here?

thanks and regards
S Sarath
 
My observation is that (taped) LED + LDR combination can give you full range of resistances based on current (and hence brightness) flowing through LEDs.

I have been able to measure resistances of 50 ohms (for brightest light, about 60-80mAmp current in LED) to few mega ohms when it is dark. I chose off-the-shelf 5mm LDR and brighter white LEDs. (Normal RED LEDs are not so bright, and min resistance you can get is around 125-150 ohms.)
 
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