Good afternoon folks,
I am trying to build a circuit to control a very small DC motor for a hobby project im working on.
I am looking to calculate the base resistor(R1) value.
My search online found this equation.
R = Vc / (MMC / HFE * 1.3)
VC = Input Collector Voltage.
MMC = Maximum Current needed to drive the Motor.
HFE = Minimum HFE/Beta (DC Current Gain)
This equation allows for 30% more heat exchange for safety purposes.
The values I am using are as follows.
VC = +12V
MMC = 1000ma (1 Amp)
HFE = 63
The resistor value returned by my calculations is 0.58 ohms.
And this seems very odd.
Please note too that the logic level voltage used to control the base of the transistor will not excead +5V as it is connected to my MCU.
I am using group 10 version of this transistor.
Here is the link to the datasheet.
http://www.datasheetcatalog.org/data...fa3reo8uky.pdf
I have included a diagram attachment of the circuit I'll be using.
Please help me figure this out. Thanks a million.
I am trying to build a circuit to control a very small DC motor for a hobby project im working on.
I am looking to calculate the base resistor(R1) value.
My search online found this equation.
R = Vc / (MMC / HFE * 1.3)
VC = Input Collector Voltage.
MMC = Maximum Current needed to drive the Motor.
HFE = Minimum HFE/Beta (DC Current Gain)
This equation allows for 30% more heat exchange for safety purposes.
The values I am using are as follows.
VC = +12V
MMC = 1000ma (1 Amp)
HFE = 63
The resistor value returned by my calculations is 0.58 ohms.
And this seems very odd.
Please note too that the logic level voltage used to control the base of the transistor will not excead +5V as it is connected to my MCU.
I am using group 10 version of this transistor.
Here is the link to the datasheet.
http://www.datasheetcatalog.org/data...fa3reo8uky.pdf
I have included a diagram attachment of the circuit I'll be using.
Please help me figure this out. Thanks a million.
Attachments

13.3 KB Views: 263