I want to run a 3.3v coreless dc motor with arduino pro mini. Since the current supplied is not enough so I connected the pin of arduino as base of the transistor. the emitter is supplied with 3.7v 600mah lipo battery. please help me in finding the base resistor of the transistor.
does the biasing resistor is the 2n2222 transistor depends upon the supply mah of the battery? i.e do I need to use different biasing resistor if I use 300mah instead of 600mah??
supply used:3.7v lipo
transistor used:2n2222
used to run a coreless dc motor,motor has a resistance of 15ohms.
Post a photo of a hand drawn schematic. We don't like to use words to describe circuit connections. That usually only works if all the parties involved are professsional working electronics technicians. It doesn't work very well with beginners.
this schematic diagram was given on the web page from where I got the idea of the project. but when I use 100ohm resistors the motors are not working with full speed. the biasing resistor given in the schematic is wrong. what should be the actual value of the resistor??
Look at the part number on the transistors and verify that is does NOT say P2N2222A. (because the pinout for that one is reverse of the 2n2222.
Measure:
1- the Lipo battery voltage
2- transistor base voltage
3-3.3V pin (Vcc) on the Pro-Mini
Post the values.
Post a link for the motors that shows their specs
NOTE: > the pin of arduino as base of the transistor. the emitter is supplied with 3.7v 600mah lipo battery. please help me in finding the base resistor of the transistor.
Your word discription does NOT match the schematic.
the pin of arduino as base of the transistor
THIS is just plain WRONG. The arduino does NOT connect to the transistor. It connects to the base resistor.
the emitter is supplied with 3.7v 600mah lipo battery
THIS is just plain WRONG. The battery DOES NOT connect to the transistor. It connects to the motor.
In your circuit, you are not actually biasing - technically. So, maybe not the best use of the term.
In your design, you are trying to get a 2N2222 to turn on hard and allow high collector current.
Roughly 30 mA in the base pin will do it. The values supplied would work so my advice is don't jump to the conclusion that it is the value of the base resistor that is holding you back.
The problem could be even related to limited battery current. Not all 2222's are created equal ans some will not operate at the max current we assume the 2222 will allow.
The problem could be even related to limited battery current. Not all 2222's are created equal ans some will not operate at the max current we assume the 2222 will allow.
It's impossible to find a lipo battery these days that has a rating less than 25C
The OP failed to mention the mAh rating so that is an unknown.
If it was a 750 mAh rated battery it could source no less than 25 * 0.75A = 18.750 A (for 1.5 minutes)
It's impossible to find a lipo battery these days that has a rating less than 25C
Not quite! I found a 20C
IF the coreless motor really is 15 ohms its fine, although the one's I've seen are 2A or more at 3.7V,
so I wonder if that 15 ohms is right. 2A is far too much for a 2N2222
I am new to all this use of transistors. I want to know how you determined how much will be the base current for a 2n2222 transistor to turn on when a supply of 3.7v 600 mah lipo is used??
and since a 2n2222 can only give 800ma ,so can anyone suggest me a way to increase the current that goes into the motor??
i was thinking of using some other transistor
That is the maximum, you should not be running this transistor at anything greater than 500mA.
a 2n2222 transistor to turn on when a supply of 3.7v 600 mah lipo is used??
That is not a question, or at least some important information is missing. The current from collector to emitter is determined by the collector voltage and the current. The current is set by the resistance of your load. You make no mention of what your load is.
You want the transistor to go into saturation so look for the value of base current needed for saturation in the data sheet.
so can anyone suggest me a way to increase the current that goes into the motor?
Simply increase the voltage, there is nothing else that you can do. Look up ohms law.
