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From: Kari Laine on 27 Apr 2010 10:50 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)
From: Peter Bennett on 27 Apr 2010 12:06 On Tue, 27 Apr 2010 17:50:39 +0300, Kari Laine <klaine8(a)gmail.com> wrote: >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 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
From: Kari Laine on 27 Apr 2010 14:27 Peter Bennett wrote: > On Tue, 27 Apr 2010 17:50:39 +0300, Kari Laine <klaine8(a)gmail.com> > wrote: > >> 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 > > Connect a resistor from a digital output to the positive supply, then > measure the voltage between the digital output and ground. > > THANKS ! -- PIC - ARM - DISPLAYS - RELAYS - MODULES - CONVERTERS - I2C - SPI - KEYPADS - ACCESSORIES http://www.byvac.com (I am just a satisfied customer)
From: John Fields on 27 Apr 2010 13:01
On Tue, 27 Apr 2010 17:50:39 +0300, Kari Laine <klaine8(a)gmail.com> wrote: >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 ... --- Try this: (View in Courier) C-------+ VIN>---[R]----B NPN |+ E [OHMMETER] | |- GND>------------+-------+ or this: C-------+ VIN>---[R]----B PNP |- E [OHMMETER] | |+ VCC>------------+-------+ JF |