14.6 CHAPTER 14. ELECTRONICS
- The instantaneous value ofVRchanges but inductive reactance, which is the ratio
of the maximum values,is useful, XL. - The impedance is the maximum voltage dividedby the maximum current in the
circuit. - Inductors and capacitors affect circuits in frequency dependent way.
- A capacitor blocks lowfrequencies and allows high frequencies to pass.
- An inductor blocks high frequencies and allows low frequencies to pass.
- Active circuit components change their behaviour in a circuit and include diodes
and field effect transistors. - Digital electronics arebased on logic gates (NOT, AND, OR, NAND and NOR)
that take discrete voltagevalues as input. - Each one makes its decision in a different way and can be represented by a truth
table.
Chapter 14 End of Chapter Exercises
- Calculate the reactance of a 3 mH inductor at a frequency of 50 Hz.
- Calculate the reactance of a 30 μF capacitor at a frequency of 1 kHz.
- Calculate the impedance of a series circuit containing a 5 mH induc-
tor, a 400 μF capacitor and a 2 kΩ resistor at a frequency of 50 kHz. - Calculate the frequency at which the impedance of the circuit in the
previous question will be the smallest. - Which component can be used to block lowfrequencies?
- Draw a circuit diagram with a battery, diode and resistor in series.
Make sure that the diode is forward biased so that a current will flow
through it. - When building a complex electronic circuit which is going to be pow-
ered by a battery, it is always a good idea to puta diode in series with
the battery. Explain howthis will protect the circuit if the user puts
the battery in the wrongway round. - Summarise the differences between a bipolar and field effect transis-
tor. - What does an operational amplifier (op-amp)do?
- What is the difference between a digital signal and an analogue sig-
nal? - What are the advantages of digital signals over analogue signals?