Hello, i have a circuit shown bellow which is taken from an attached presentation.
Ifi understand it correctly i need to supply DC current for 2u FM coil.
the presentation slide bellow misses info.
i know that R3 R7 for BC807-40 PNP above is for biasing.
I have few questions:
1.At what state do you think the PNP is in?
the table bellow shows the PNP states and i am not sure to what state should i bias the PNP?

2. Suppose at some point the VFM voltage rises from V0 to V0+0.01V So V_minus of the opamp rises too,So what causes the voltage on VFM to return to V0?
Thanks.

 

Keep in mind that the base of that PNP is connected to the + power input of the opamp. What is the
current to the opamp doing and where is it going?

 

Hello Michael , Suppose at some point the VFM voltage rises from V0 to V0+0.01V So V_minus of the opamp rises too,So what causes the voltage on VFM to return to V0?

 

The output of the opamp goes lower which lowers the current through L1 and R2.