- #1
medosoft
- 6
- 0
How to increase the current?!
I'm designing a drive circuit for a 12V DC motor
I'm using a (2N3055 BJT) as a switch to control the output, and I'm using a (74121 monostable oneshot) to control the BJT switch.
So, the output of the 74121 is fed into the base of the BJT.
Here is the schematics for my circuit
http://img594.imageshack.us/img594/7411/etpcircuit.jpg
According to the datasheet of the BJT, β=100. Which means that the current supplied to the base should be at least 1/100 of the current that is supposed to run through the collector. The motor needs about (2-3) Amps to run at a proper speed, meaning that the base current should be at least (20 - 30 mA).
The problem is that the output current of the 74121 ranges from (4 - 16 mA).
Is there anyway to increase the current?
I can sacrifice some of the voltage
I'm designing a drive circuit for a 12V DC motor
I'm using a (2N3055 BJT) as a switch to control the output, and I'm using a (74121 monostable oneshot) to control the BJT switch.
So, the output of the 74121 is fed into the base of the BJT.
Here is the schematics for my circuit
http://img594.imageshack.us/img594/7411/etpcircuit.jpg
According to the datasheet of the BJT, β=100. Which means that the current supplied to the base should be at least 1/100 of the current that is supposed to run through the collector. The motor needs about (2-3) Amps to run at a proper speed, meaning that the base current should be at least (20 - 30 mA).
The problem is that the output current of the 74121 ranges from (4 - 16 mA).
Is there anyway to increase the current?
I can sacrifice some of the voltage
Last edited by a moderator: