How are transistors different?

Question

Electronic components

Hello!
I want to ask you about transistors. I read a lot of different things about them and about switching schemes. But I have not figured out the parameters yet. I experimented a lot, but I did not understand some things. The situation is as follows:
I have assembled a circuit with an npn transistor (2n 2222) with a common base. The signal comes from the Arduino microcontroller. Plus (pin) is connected to the base of the transistor, minus (gnd) is connected to the emitter, the controller sends a signal that turns on and off after a second.
The output is connected to an LED. The output scheme is as follows: an external 5V battery is used. the negative of the battery goes to the base of the transistor, the collector of the transistor is connected to the LED, and the second pin of the LED goes to the positive of the battery. With this scheme, the LED blinks normally, as it should. but if you connect an electric motor instead of an LED, then it does not work, although the motor itself is working.
I measured the output voltage - it is approximately 5V. when switched on, as my intuition tells me, the motor does not work due to insufficient current at the output.
Accordingly, my questions are:
do I think correctly about the current strength in my circuit?
Is there a fundamental difference in practice in using pnp or npn transistors (except in the wiring diagram)?
What transistors for what purposes do you recommend using? (as I understand it, the 2n 2222 transistor (only I had it in stock) is well suited for electronic circuits with a small current strength, and something else is needed to power the motors)
Thank you for your attention.

Answer 1

In order.
0) Draw, however, a diagram, it is very hard to perceive by ear.
1) PNP and NPN transistors differ in their switching polarity. Roughly speaking, when the “minus” of the power supply is grounded, and the amplified signal is positive (your case), an NPN transistor is needed. Otherwise, PNP. You can't just replace one with the other.
2) A circuit with a common base is not suitable here; an emitter follower is usually used to control the load . If the load supply voltage is greater than the input voltage (say, a separate 12-15V source is used), then a circuit with a common emitter .
3) Between the output of the controller and the base of the transistor, it's a good idea to include a resistor of several kOhm to limit the base current.
4) There are two main parameters of the transistor: the current gain and the maximum allowable collector current. With the allowable current, the 2n2222 is all right, 800 mA is enough for a small motor. He has a gain of about 75. What does this mean? Let 5V be supplied to the base through a 2kΩ resistor. The base current will be approximately (5-0.7) / 2000 = 2.2mA. So the collector current (load current) will be 2.2*75=165mA. It may not be enough for the engine. More details about the calculation of the transistor mode can be found here: www.trzrus.narod.ru/calc/trzbr.htm
5) If there is not enough current gain, use a composite transistor .
6) If you need to change the polarity of the voltage on the load, use the H-bridge, as Melz said. Such bridges are produced in the form of ready-made microcircuits, there is no need to be smart.
7) In parallel with the transistor (between the collector and emitter), it is good to turn on the diode in reverse polarity to protect against self-induction EMF. This should be done whenever there is an inductive load: motors, relays, electromagnets.

Answer 2

> am I thinking correctly about the current strength in my circuit?
You can look at the spec on the electric motor.

Answer 3

Draw a diagram. So it's hard to understand by ear.
"Regular" Chinese motors like:
www.conrad.de/medias/global/ce/2000_2999/2200/2280/2289/228959_LB_00_FB.EPS_250.jpg
operate on 4-14 volts. Connect it directly to the battery and see if it spins or not. It's 100% normal DC.
Look for H-bridge to connect.
modularcircuits.tantosonline.com/blog/articles/old-h-bridge-secrets/part-1/

Answer 4

Thank you. I apologize for not answering for a long time. I'm going to learn materiel.

Answer 5

Thanks for the hints. I made an amplifier with a common emitter, everything worked as I wanted.