Single Emitter Bar Code Optic Head OTBC-04XX Series (OTR480/490/482)
Suggested Application Circuit
The above circuit represents an adaptive dual peak detector with a first stage transimpedance amplifier. This circuit is
recommended for typical bar code or fine element sensing applications using the OTBC-04XX series optic heads. The first amplifier
servers as a current-to-voltage amplifier (transimpedance). The second part of the circuit provides positive and negative peak
detection. The peak voltages are temporarily stored in the 0.1 µF capacitors. The comparator reference is approximately 45% of
the peak-to-peak amplitude. This, in effect, provides an adaptive threshold to the comparator based on the voltage peaks of the
incoming signal. The 2.2 MΩ resistor on the last stage (indicated with an *) sets the positive feedback, and combined with the 10 kΩ
input resistor the hysterisis is set to approximately 25 mV. Setting the 2.2 MΩ resistor to 100 kΩ will increase the hysterisis to 500
mV, but response will be sacrificed. Vout is low for reflectance and high (+5V) for no reflectance (i.e., sensing a dark mark).
Ordering Information
OTBC-04X X-XX
Emitter:
Aperture Size:
(0) 0.006” x 0.090”
(C) Custom
(8) 940 nm Infrared
(9) 660 nm Visible Red
Number of Channels:
Sensor:
(1) 1 channel
(0) Phototransistor
(2) 2 channels
(NN) NN channels
(2) Phototransistor w/ ambient filter
Note: Option 2 available with infrared emitter only.
Note: Test capability to better than 0.003”
channel-to-channel alignment available.
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