Pc_Tan
Posts: 2
Joined: Wed Nov 26, 2014 11:33 pm
Occupation: Student: college first year

bristlebot suggestion

Postby Pc_Tan » Wed Nov 26, 2014 11:50 pm

Hi, I am currently conducting the project 'build a light-tracking bristlebot'.
For the base circuit, can I connect the photoresistor in series with the potentiometer and the gate of the MOSFET?

rmarz
Expert
Posts: 587
Joined: Sat Oct 25, 2008 1:26 pm
Occupation: Technology Consultant

Re: bristlebot suggestion

Postby rmarz » Thu Nov 27, 2014 9:53 am

Pc_Tan - Simple answer, no. The FET is controlled by a voltage level that is established by the photoresistor and potentiometer. The FET is has such a high input resistance, that it would likely 'see' the full battery voltage instead of the voltage established at the node of the photoresistor and potentiometer if simply connected in series as you suggest. If the FET was, in fact, a bipolar transistor that reacted to BASE current, your idea might be valid. What was your thought about changing the circuitry? Curious.

Rick Marz

Pc_Tan
Posts: 2
Joined: Wed Nov 26, 2014 11:33 pm
Occupation: Student: college first year

Re: bristlebot suggestion

Postby Pc_Tan » Thu Nov 27, 2014 7:47 pm

Rick - Thanks for your advice. I was thinking If I can adjust the sensitivity of photoresistors in another way stated in the project but it seems that it won't work.


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