Open Collector?

Apr 27, 2010 3 Replies
K

Hi,



I just built Velleman 8061 and got it eventually working - I think?



But I have a question.



Shouldn't I be able to see whether line is active by resistance meter over the transistor?



If I have understood right the resistance over the transistor should change when line is on or off?



Now the resistance meter shows only infinity whether the line is 0 or 1.



I can't understand ...



Best Regards Kari


PIC - ARM - DISPLAYS - RELAYS - MODULES - CONVERTERS - I2C - SPI - KEYPADS - ACCESSORIES http://www.byvac.com (I am just a satisfied customer)
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P

Connect a resistor from a digital output to the positive supply, then measure the voltage between the digital output and ground.

Peter Bennett, VE7CEI peterbb4 (at) interchange.ubc.ca GPS and NMEA info: http://vancouver-webpages.com/peter Vancouver Power Squadron: http://vancouver.powersquadron.ca
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J

Try this: (View in Courier) C-------+ VIN>---[R]----B NPN |+ E [OHMMETER] | |- GND>------------+-------+ or this: C-------+ VIN>---[R]----B PNP |- E [OHMMETER] | |+ VCC>------------+-------+ JF
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K

THANKS !

PIC - ARM - DISPLAYS - RELAYS - MODULES - CONVERTERS - I2C - SPI - KEYPADS - ACCESSORIES http://www.byvac.com (I am just a satisfied customer)
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