Hi all,

I'm slowly learning electronics and trying not to rely on the simulator too much.

I'm building a simple 3 transistor am radio from a circuit found online and while waiting for the bits I am trying to understand the circuit a bit more.

A section of the circuit I have extracted but am struggling to methodically solve it... I have looked at various tutorials and am assuming that I need to use KVL and KCL plus simultaneous equations to solve but not sure where to begin.?

Any help appreciated circuit is attached.

Thanks

 

What is it that you want to determine?

 

What is it that you want to determine?

I can see all the values at each node for voltage and current in the simulator but I want to be able to find these values without relying on the simulator.

It's a slightly different setup to most circuits I have seen with the base current having to pass through 2 resistors and the collector current only passing through 1. I know the transistor will likely drop around 0.7 volts between the base and emitter and around 0.2 volts between the collector and emitter, but unsure how to sold the circuit and where to begin solving it?

 

You can start by writing the KVL equation




Vcc = V_Rc + Vce = I1*Rc + Ib1*RB + Vbe

Also, notice that I1 = Ic1 + Ib1 (from KCL) but we also know that Ic = β*Ib therefore:

I1 = β*Ib1 + Ib = (β + 1)*Ib1

And finally we have:

Vcc = (β + 1)*Ib1*Rc + Ib1*RB + Vbe

And we can solve for Ib1:

Ib1 = (Vcc - Vbe)/(RB + (β + 1)*Rc ) = (9V - 0.7V )/(560kΩ + 101*10kΩ) = 5.28μA and Ic1 = 100*5.28μA = 528μA.

And

Vce = Vcc - I1*Rc = Vcc - (β+1)*Ib*Rc = 9V - 101*5.28μA*10kΩ = 3.66V

Also, try to read this if you want to see a different approach
https://electronics.stackexchange.c...iescent-voltage-and-active-mode/418257#418257