Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: Its_Friday on March 12, 2009, 04:36:39 PM
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I'm building 2 encoders using 2 IR LEDs, 2 optical switches, and an ina126 dual amplifier (http://focus.ti.com/lit/ds/symlink/ina126.pdf). My main question is "what is gain?" It says i can set the gain anywhere from 5V/V to 10000V/V but i don't know how much gain (ballpark range) i need for a normal axon microcontroller to read the signal.
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Hi,
Gain is the amplification factor.
5V/V means you get 5V out for every 1V in which means that the gain (Av) is 5.
10000V/V is simply a gain of 10,000 (times).
The amount of gain needed can be calculated by: Uo/Uin
(Where Uo = output voltage needed and Uin = input voltage available).
You probably want Uo=5V, but without knowing the schematic of your circuit, I cannot tell you what gain you need.
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Thank you. That cleared things up for me.
My schematic uses an IR LED and an optical switch, it looks similar to this one (http://www.societyofrobots.com/images/schematics_infraredemitdetamp.jpg). The only big difference is that mine uses a different IC.