How to work with bipolar transistors?

Question

Electronics

Hello. Confused in 2 Christmas trees, please explain what's what.
I have a task - I need to turn on the radio using a signal from the Raspberry Pi. The buttons are arranged simply, roughly speaking, 2 wires. You close, the radio turns on. The most obvious solution is to insert a transistor (emitter and collector on the wires from the radio button), apply current to the base with raspberry. The transistor chose this 2n2222a Please help in general terms to determine what current should be allowed to the base so that the transistor opens completely? What happens if the base current is greater than the collector current?

Answer 1

But you don’t have to suffer with bipolar ones where you need a field one!
We put an n-channel transistor with the desired characteristics to tighten the “minus” of the power supply - voila!
In old motherboards, there are a lot of different field workers with the right characteristics.

Answer 2

In order to answer correctly, you need to know where the contacts from the button in the walkie-talkie lead? If one of them goes to the "-" power of the radio, then a bipolar npn with a resistor at the base input of about 5 kOhm is well suited, a collector to the second contact of the button and an emitter to the "-". Of course, the common chains of the raspberry and walkie-talkie must be connected.
If there is no "-" or "+" on the contacts of the radio button, then you need to look at which circuit is closed by the button, and then write here.