Maker Pro
Maker Pro

Photodiode light sensing switch

vishnums

Feb 18, 2015
1
Joined
Feb 18, 2015
Messages
1
new.png

I have the abouve circuit. It doesn't work. I keep on getting HIGH in the signal...How can I check it. Is there any problem with biasing.please help.
 

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,700
Joined
Nov 17, 2011
Messages
13,700
Welcome to electronicspoint.

The photodiode may not generate enough current to drive the transistor. What type of photodiode are you using (attach datasheet, please)?
Try to increase the value of R5 to e.g. 100kΩ - what happens?
 
Top