Let's Make Robots!

npn

many little motors, many power supply questions

Hi all,

 

I am new to this forum but i have stalked users of this site for sometime.

I have a project on the go that i am a little stuck on. I have come pretty far since the idea hit me many months ago but now i am at the tail end and wondering how i will power this thing.

I have been using an Arduino connected to a bunch of 595 shift registers which are then connected to 36 small dc motors via npn transistors. the motors are small mobile phone vibrating motors and i need them to run, as per datasheet, 3v @ 90ma.

 

So after lots of hard-work, frustation, time, spending money on wrong parts; I built a robot. Its a Photovore based on NPN transistors. when its LDRs are pointed … Read more

A IC form of NPN transistor ?


Is there  such thing as a DIP package of transistors ? (not sure if that is the right way to put it) 
 
I need to control 12 digital connections and putting 12 transistors on a PCB will take up a decent amount of space 
so I was wondering if there is a chip like version.
 
If possible a high voltage ~40V and high amperage trnasistor would be perfect it it exists. 

Transistor Confusion (again)

Greetings fellow meatbags.

Calculon is trying to hook up a pimpin motor to his Mr Basic, and has come across something very confusing with his transistor.

Here's what he's trying to do with a nte123 pulling a seperate power supply to a motor made for 3v:

transquestion2.gif

He also tried it with a 2n3904. It didna work for either. According to his understanding of NPN transistors, the output from the picaxe should switch on the tran, and pull the 3v through the motor. No?

NPN vs PNP, a fundamental or just a mental difference

Like many here, I were in need of a bit of amplification of a weak signal. This signal had "low impedance", I suppose. The supplied circuit diagram shows two different ways of meeting my need.

The left circuit uses a NPN transistor. The right hand circuit uses a PNP transistor. I chose the one with PNP. Quite "arbitrarily". The BP103B is also known as FA300.