CHAPTER 14. ELECTRONICS 14.4
- A radio station broadcasts at a frequency of 150 kHz. The tuning circuit in the ra-
dio contains a 0.3 mH inductor. What is the capacitance of the capacitorneeded
in the tuning circuit if you want to listen to this radio station? - State the relationshipbetween the phase of the voltages across an inductor, a
resistor and a capacitorin an LRC circuit. - Explain what is meant by resonance.
- Explain how LRC circuits are used for signal tuning, for example in aradio.
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(1.) 01jb (2.) 01jc (3.) 01jd (4.) 01je (5.) 01jf (6.) 01jg
(7.) 01jh (8.) 01ji
14.4 Active Circuit Elements
ESCGF
The components you have been learning about so far — resistors, capacitors and induc-
tors — are called passive components. They donot change their behaviour or physics
and therefore always have the same response tochanges in voltage or current. Active
components are quite different. Their response tochanges in input allowsthem to make
amplifiers, calculators and computers.
The Diode ESCGG
A diode is an electronicdevice that allows current to flow in one direction only.
direction of current
+−
Figure 14.8: Diode circuit symbol and directionof flow of current.