Electronics4you
Member
Hi there,
I have to run a 12V motor in both directions. I have build a prototype schematic below. The transistor used is the BD911 (PNP) and BD912 (NPN) with a max current through collector-emitter of 15A. I have some questions to the circuit
1. Do I need an ULN2003 with 12V to turn the PNP transistor ON/OFF, or can it be done in other (cheaper) ways from the PIC?
2. To get 5-6A through the bridge, do I then have to change the 1k resistor to a smaller, because of the transistors amplification on min. 25gg?
3. How do I calculate the total amount of current avaible to the motor concidering both hfe, base current,,...?
Thanks
I have to run a 12V motor in both directions. I have build a prototype schematic below. The transistor used is the BD911 (PNP) and BD912 (NPN) with a max current through collector-emitter of 15A. I have some questions to the circuit
1. Do I need an ULN2003 with 12V to turn the PNP transistor ON/OFF, or can it be done in other (cheaper) ways from the PIC?
2. To get 5-6A through the bridge, do I then have to change the 1k resistor to a smaller, because of the transistors amplification on min. 25gg?
3. How do I calculate the total amount of current avaible to the motor concidering both hfe, base current,,...?
Thanks
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