13-09-2017, 01:18 PM
Digital circuits are circuits that deal with signals restricted to the extreme limits of zero and some total amount. This contrasts with analog circuits, in which the signals are free to vary continuously between the limits imposed by the supply voltage and the resistances of the circuit. These circuits find use in "true / false" logic operations and digital computing.
Circuits in this chapter use integrated circuits or integrated circuits. Such components are actually interconnected component networks made of a single wafer of semiconductor material. Integrated circuits that provide a multitude of pre-designed functions are available at very low cost, benefiting students, amateurs and professional circuit designers alike. Most integrated circuits provide the same functionality as "discrete" semiconductor circuits at higher levels of reliability and at a fraction of the cost.
The circuits in this chapter will mainly use CMOS technology, as this form of IC design allows a wide range of power supply voltage while maintaining generally low levels of power consumption. Although CMOS circuits are susceptible to damage by static electricity (high voltages will pierce insulation barriers in MOSFET transistors), modern CMOS ICs are much more tolerant to electrostatic discharge than the ICS CMOS of the past, reducing the risk of failure of chips for poor management. Proper handling of CMOS involves the use of antistatic foam for the storage and transport of integrated circuits and measures to prevent static charge from accumulating in your body (use of a wrist strap to ground, or frequently touching an object connected to Earth).
Circuits using TTL technology require a regulated voltage of 5 volts, and will not tolerate any substantial deviation from this voltage level. Any TTL circuit in this chapter will be properly labeled as such, and expected to account for your unique power supply requirements.
When building digital circuits that use "circuits" of integrated circuits, it is highly recommended that you use a test board with "rail" connections to the power supply along its length. These are sets of holes in the bread plate that are electrically common throughout the entire length of the plate. Connect one to the positive terminal of one battery and the other to the negative terminal, and DC will be available for any area of the test board via short jumper cables:
With so many of these integrated circuits having "reset", "enable" and "off" terminals that need to be kept in a "high" or "low" state, not to mention the VDD (or VCC) terminals require connection to the source power supply, having both power supply terminals readily available for connection at any point along the length of the card is very useful.
Circuits in this chapter use integrated circuits or integrated circuits. Such components are actually interconnected component networks made of a single wafer of semiconductor material. Integrated circuits that provide a multitude of pre-designed functions are available at very low cost, benefiting students, amateurs and professional circuit designers alike. Most integrated circuits provide the same functionality as "discrete" semiconductor circuits at higher levels of reliability and at a fraction of the cost.
The circuits in this chapter will mainly use CMOS technology, as this form of IC design allows a wide range of power supply voltage while maintaining generally low levels of power consumption. Although CMOS circuits are susceptible to damage by static electricity (high voltages will pierce insulation barriers in MOSFET transistors), modern CMOS ICs are much more tolerant to electrostatic discharge than the ICS CMOS of the past, reducing the risk of failure of chips for poor management. Proper handling of CMOS involves the use of antistatic foam for the storage and transport of integrated circuits and measures to prevent static charge from accumulating in your body (use of a wrist strap to ground, or frequently touching an object connected to Earth).
Circuits using TTL technology require a regulated voltage of 5 volts, and will not tolerate any substantial deviation from this voltage level. Any TTL circuit in this chapter will be properly labeled as such, and expected to account for your unique power supply requirements.
When building digital circuits that use "circuits" of integrated circuits, it is highly recommended that you use a test board with "rail" connections to the power supply along its length. These are sets of holes in the bread plate that are electrically common throughout the entire length of the plate. Connect one to the positive terminal of one battery and the other to the negative terminal, and DC will be available for any area of the test board via short jumper cables:
With so many of these integrated circuits having "reset", "enable" and "off" terminals that need to be kept in a "high" or "low" state, not to mention the VDD (or VCC) terminals require connection to the source power supply, having both power supply terminals readily available for connection at any point along the length of the card is very useful.