cough-e
Newbie level 3
Hi
I am planning on voltage-regulating the speed of a DC-motor using a "R/2R" ladder (DAC).
https://en.wikipedia.org/wiki/Resistor_ladder
A picture of my schematics is posted below. Intending to use 4 bits resolution, wich I get from atmega32 avr. Each bit is amplified trough a transistor, because I cannot drain much current from the microcontroller, and to be shure not to damage it. All transistor switches are working fine, I have driven the motor trough all of them individually. I have also testet the counting bit-pattern to be correct, using the onboard LED on my stk500. My DAC shares both VCC and GND-potential with microcontroller. It's when I connect the ladder nothing happens when I count up the bit-pattern.
What could be the error here?
My schematics are pictured here:
**broken link removed**
I am planning on voltage-regulating the speed of a DC-motor using a "R/2R" ladder (DAC).
https://en.wikipedia.org/wiki/Resistor_ladder
A picture of my schematics is posted below. Intending to use 4 bits resolution, wich I get from atmega32 avr. Each bit is amplified trough a transistor, because I cannot drain much current from the microcontroller, and to be shure not to damage it. All transistor switches are working fine, I have driven the motor trough all of them individually. I have also testet the counting bit-pattern to be correct, using the onboard LED on my stk500. My DAC shares both VCC and GND-potential with microcontroller. It's when I connect the ladder nothing happens when I count up the bit-pattern.
What could be the error here?
My schematics are pictured here:
**broken link removed**
