Hi again dear audioguru,
(still playing with fundamental of electronics)
I found a post here where you were calculating Vb, Ib and bias resistor with Vc, Ic and hFE. That was so clear to me. But I saw a circuit where used a base resistor is extremely high 10 Meg. It is a crystal radio amplifier.
(also i found a VLF receiver with a single jEET which has 44 Meg resistor for base bias and this base was antenna too. And collector of the device was connected to Mic in. I can attach it if you want.)
You were calculating with 1 Meg base resistor with almost 110 to 800 hFE. Here this transistor has almost same hFE around 200-300 BUT what is the purpose to use such large value resistor here (like 10 Meg here or 44 Meg on jFET)? Should we have to use larger R if base input has smaller signal?
Are there any interesting Vb, Ib, hFE, Ic, Vc etc. calculation related with the circuit? Thank you.