I bought a kit with Arduino Uno to do some tests. One of projects suggested say to control a DC motor 3 Vdc/300 mA with these features:
• Voltage: operating 1,5 - 3 Vdc; nominal: 3 Vdc
• Without load: 14200 rpm; 0,3 A
• With load: 11780 rpm; 1,33 A; torque: 19,6 gcm; 2,37 W; efficiency: 59,5%
• Stall torque: 115 gcm
It is suggested to use a transistor BC 547 (see attachment), using the 3.3 V Arduino source (if i don’t wrong, it can source at most 50 mA: http://arduino.cc/en/Main/ArduinoBoardUno). The circuit proposed don’t plan any base resistor or fly-back diode.
- what does it mean with the indication “3 Vdc/300 mA” for the DC motor? In what conditios does it sink 300 mA?
- I think the BC 547 isn’t sufficient to control the motor (Icmax = 100 mA). Is it correct? And what about the start current?
- Isn’t advisable a base resistor to limit the current?
I beg your pardon for my English… I hope you’ll undestand!
Thanks for replies!
BC547.pdf (47 KB)