I have some trouble understanding a basic concept. Here is my question.
This is from a document which can be found on the website,
The text accompanying this figure states, “The voltage signal produced by sound modulates the gate voltage of the JFET, labeled VG in Figure 2 causing a change in the current flowing between the drain and source of the JFET (IMIC). An extremely high resistance, RG, may be included to bias the gate of the JFET.”
I have a question regarding the above statement,
- Why is the resistance RG needed after all?
If the Voltage produced by the sound changes the current between the Drain and the Source, what is the role of the Resistor? Can't the circuit work without the resistor? I can read from the document it says the Resistor biases the gate of the JFT. I don’t understand what this ‘bias’ means. What does it mean to ‘ bias X/Y”?