Connect Var. Capacitor to Inductor for Series Radio Tuner

[Idea04]

How do you connect a variable capacitor to an inductor to make a series radio tuner?
And where do you tap the resonant frequency to send to the RF amplifier?

 

[vk6kro]

Do you mean: how would you use a series tuned circuit to tune the input of a radio receiver?

The series tuned circuit is able to give a very large voltage step-up if you have a low impedance source driving a high impedance load. The circuit has no power gain, so it converts a low voltage at high current to a higher voltage at a lower current.

This depends for its success on the antenna and also it will depend on the frequency for a given antenna.

I will attach a possible circuit. For the circuit to be of much use, I have shown a tapped inductor which may allow for the use of practical antennas.

The series circuit, though, is just the inductor and the variable capacitor.

 

[oswaler]

To connect a variable capacitor to an inductor for a series radio tuner, you will need to first determine the resonant frequency of the circuit. This can be done by using the formula 1/2π√(LC), where L is the inductance of the inductor and C is the capacitance of the variable capacitor.

Once you have the resonant frequency, you can adjust the capacitance of the variable capacitor to match it. This can be done by rotating the plates of the capacitor to increase or decrease the capacitance.

To tap the resonant frequency and send it to the RF amplifier, you will need to connect the output of the inductor to the input of the RF amplifier. This can be done by using a wire or a coaxial cable. The RF amplifier will then amplify the signal and send it to the rest of the radio circuit.

It is important to note that the exact placement of the resonant frequency tap will depend on the specific design of the series radio tuner. It is recommended to consult the circuit diagram or seek guidance from a professional to ensure proper placement and functioning of the tuner.