Razvan
New Member
Hello everyone, I have this problem where i need to propose the supply/input voltage and the output current (that I want to obtain) and then to calculate and choose the correct components so my circuit can work.
So, I choose the supply to 5V and the output that i want to obtain to 20mA. From my calculations, I got R = 250ohms, and i choose it 270ohms (standard). But now, my teacher wants to calculate the values for the NPN transistor and choose one properly (I choosed bc107a, but i dont think it's good, because i didn't make any calculations). I also tried to do my best with the schematic in orcad.
Can i get a little help?
![asd.png asd.png](https://www.electro-tech-online.com/data/attachments/95/95296-ab81e74104db3b9cc8708967811dfab7.jpg)
So, I choose the supply to 5V and the output that i want to obtain to 20mA. From my calculations, I got R = 250ohms, and i choose it 270ohms (standard). But now, my teacher wants to calculate the values for the NPN transistor and choose one properly (I choosed bc107a, but i dont think it's good, because i didn't make any calculations). I also tried to do my best with the schematic in orcad.
![asd2.png asd2.png](https://www.electro-tech-online.com/data/attachments/95/95297-07b48a288ffa8089b571a71a618977db.jpg)
Can i get a little help?