Integrated circuits Flashcards
What are integrated circuits (ICs)?
Integrated circuits (ICs) are a combination of several electronic components in a common housing, providing a very high density of components in a compact arrangement.
What are two major advantages of ICs?
The major advantages of ICs are their compact size and high resistance to mechanical stress.
What is one significant disadvantage of ICs?
A significant disadvantage of ICs is that they cannot be repaired; a defective IC must always be replaced.
Name three components usually integrated into ICs.
Semiconductors (transistors, diodes), resistors, and capacitors are usually integrated into ICs.
Why are inductances typically not integrated into ICs?
Inductances are typically not integrated into ICs due to their large space requirements.
In what types of devices can ICs be found?
ICs can be found in all modern appliances, both analogue and digital.
What is the basic function of logic circuits on ICs?
Logic circuits on ICs perform desired functions by manipulating signals through logic gates, representing binary 1s and 0s.
What is the purpose of logic gate symbols?
Logic gate symbols advise what inputs are required for the desired output.
Describe the NOT gate function.
A NOT gate, or inverter, outputs the opposite logic level to its input; if the input is 1, the output is 0, and vice versa.
What is the output of an AND gate when both inputs are 1?
The output of an AND gate is 1 only when both inputs are 1.
What condition produces a HIGH output in an OR gate?
An OR gate produces a HIGH output if at least one input is HIGH.
How does a NAND gate function differently from an AND gate?
A NAND gate functions like an AND gate followed by a NOT gate, producing an output that is the inverse of the AND gate output.
What is the truth table for a NOR gate?
The truth table for a NOR gate shows that the output is 1 only when all inputs are 0.
Describe the function of an XOR gate.
An XOR gate produces a HIGH output when exactly one of the inputs is HIGH.
What are linear integrated circuits?
Linear integrated circuits are those where a linear relationship exists between voltage and current, often used in small signal amplifiers, differentiators, and integrators.
What is a key characteristic of an operational amplifier (Op-amp)?
An operational amplifier (Op-amp) has very high gain, very high input impedance, and very low output impedance.
What type of circuits commonly use Op-amps?
Op-amps are commonly used in signal processing circuits, control circuits, and instrumentation
How does an Op-amp’s inverting input affect the output signal?
The signal applied to an Op-amp’s inverting input will be reversed in polarity at the output.
What were the primary functions of early operational amplifiers?
Early operational amplifiers were used to perform mathematical operations such as addition, subtraction, integration, and differentiation.
What components were used to construct early operational amplifiers?
Early operational amplifiers were constructed with vacuum tubes and worked with high voltages.
How are modern operational amplifiers different from early ones?
Modern operational amplifiers are linear Integrated Circuits (ICs) that use relatively low DC supply voltages and are reliable and inexpensive.
What are the input terminals of an operational amplifier called?
The input terminals of an operational amplifier are the inverting input ( - ) and the non-inverting input ( + ).
How are pins numbered on a typical DIP/DIL IC?
Pins on a typical DIP/DIL IC are numbered in an anti-clockwise direction from the top, with pin number 1 usually marked with a dot.
Why are the DC voltage terminals often left off the schematic symbol of an Op-Amp?
The DC voltage terminals are usually left off the schematic symbol for simplicity, but they are always understood to be there.
What is the Common Mode Rejection Ratio (CMRR)?
The Common Mode Rejection Ratio (CMRR) is the ratio of the change in output voltage to the change in the common mode input voltage, expressed in decibels (dB).
What is the purpose of the offset null pins on an Op-Amp?
The offset null pins are used to minimize the input offset voltage, ensuring the output voltage is zero when the input voltage is zero.
What is the open-loop gain of an operational amplifier?
The open-loop gain is the ratio of the output voltage to the input voltage measured without external feedback applied.
How does a summing amplifier work?
A summing amplifier combines several input signals into a single output that is the sum of the applied inputs.
What does a voltage follower or buffer amplifier do?
A voltage follower or buffer amplifier provides a high input impedance and a low output impedance, with an exact gain of unity.
What is an Op-Amp comparator?
An Op-Amp comparator compares one analog voltage level with another or a preset reference voltage and produces an output signal based on this comparison.
What is the function of an integrator amplifier?
An integrator amplifier produces an output voltage proportional to the integral of the input voltage over time.
What is the typical input resistance range for operational amplifiers made with FET/CMOS technology?
The input resistance range for FET/CMOS operational amplifiers is typically over
10^12
ohms, making them very sensitive to static electricity discharges.
How is the voltage gain of a non-inverting amplifier calculated?
The voltage gain of a non-inverting amplifier is calculated as
Av=1+Rf/Rin
What are the two types of feedback discussed?
The two types of feedback are negative and positive.
What is the most common type of feedback used?
Negative feedback is the most common choice.
In negative feedback, what is the effective input signal?
The effective input signal is the difference of the original input and the feedback signal.
In positive feedback, what is the effective signal at the input?
The effective signal at the input is the sum of the actual input and the feedback signal.
Where is positive feedback commonly used?
Positive feedback is commonly used in oscillator circuits.
How do input and output relate in positive feedback?
In positive feedback, the input and output are in-phase.
What happens to the output signal in positive feedback?
The output signal, which is in phase with the applied input, is fed back to the reference input, adding to the reference input signal.
How do input and output relate in negative feedback?
n negative feedback, the input and output are anti-phase.
What happens to the output signal in negative feedback?
The output signal, which is anti-phase with respect to the input, is fed back to the input, where it gets subtracted from the original input signal.
What is the signal referred to in negative feedback that corrects the output?
The signal is referred to as an error signal.
Where is negative feedback commonly used?
Negative feedback is commonly used in amplifier systems.
What are the benefits of negative feedback?
Negative feedback increases system stability, bandwidth, and input impedance, reduces distortion and noise, and decreases output impedance.
What is a disadvantage of positive feedback?
Positive feedback increases the overall gain but reduces the sensitivity of the system.
What is a disadvantage of negative feedback?
Negative feedback decreases the gain of the system.
What does the gain of the system with positive feedback look like?
The gain of the system with positive feedback is high.
What does the gain of the system with negative feedback look like?
The gain of the system with negative feedback is controlled.
why is a parallel diode circuit used in a circuit?
so that increased applied current can be used
what does a unbiased diode depletion zone consist off?
positive and negative ions
why is a transistor used in a circuit?
so that a small current at the base can turn on a large current at the collector
what must be done to a transistor to test it?
it must be removed from the circuit
what is used to stabilise the bias condition of a transistor to stabilise it?
a resistor RE on the Emitter
when does negative feedback occur in a transistor?
when the feedback is out of phase with the input
how are the DC bias voltages separated from the signal which is being amplified by the transistor?
with a coupling capacitor prior to the resistor network at the base of the transistor
how are pins and number identified on a Op-Amp?
anti-clockwise from the marked pin
what is there typical supply voltage of an Op-Amp?
from +/- 5v and +/- 15v
how many pins does an Op-Amp installed into an IC require
7 pins
