Recent content by ajack

Using thevenin equivalent is very good way to simply the circuit, because we know that the load can't "tell" the different between 2 circuits. But the thevenin's origin is really troublesome. I really don't know how to prove the thevenin's theorem or what's state of it. Kirchhoff Law has proof...

Yeah, thank for your advice. And now I understand why my teacher is really angry when I do as the 2nd diagram :P. Anyway, thank you very much!

Yes, that's right. But the matters are switching the light on. In switching mode (saturation mode), the current I_C is constant (I_C doesn't increase although you increase I_B). We only care about how to light the LED on because we use the transistor as a switch in this case. So, in this case, I...

When using transistor NPN in switch mode as 2nd diagram, I use the 6V source, and I use Q2SC1815. But the Q2SC1815's breakdown Volt of B-E Junction is 15V. That means the transistor still work in staturation mode. After doing as 2nd diagram, although what Ranger said is right, but I wonder the...

I'm really confused between saturation and amplifier. When will the transistor work in saturation mode and in amplifying mode? Resistors are the matters. We chose the resistors so that the transistor will work in saturation or amplifying. How can we chose?

In order to use BJT as a switch, it's very popular to do as the picture. In the picture, V_B > V_E, so there's a current flow I_BE control the I_CE. In the other way, V_B > V_E generates the current I_CE, and the lamp will light on. But, I change the connection a little: I'll let the V_B...