8. PASSIVE COMPONENTS
 8.4. COMBINATION OF PASSIVE COMPONENTS
 8.4.3. TUNED CIRCUIT CONNECTED TO AN AC-VOLTAGE
 (introduction...) 8.4.4.1. QUALITY OF TUNED CIRCUITS 8.4.4.2. BANDWIDTH

### 8.4.4.2. BANDWIDTH

Sometimes it is important to have a tuned circuit which lets through not only a single frequency, but a whole bond of frequencies. In this case it could be important to have a flatter graph. To be able to define the bandwidth of tuned circuit, there is again taken the value of 0.707 as limit. This means it the output voltage has dropped to 70.7 % of the output at fres the limit is reached.

CHECK YOURSELF

1. What is the difference of a series and a parallel tuned circuit?

2. What is the meaning of the terms: resonant frequency. Quality, bandwidth?

3. You have found in a radio a parallel connection of a capacitor of 10nF and an inductor with 100mH. What is the resonant frequency?

4. You want to built a tuned circuit for MW. You have a variable capacitor of 500pF. What inductance must the coil have? (500pF is the maximum value of the variable capacitor).