Exam Flashcards
What is electrical circuit?
an electric network within which at least one closed path exists and around which electric charge may flow. Connected by conducting wires
What is electrical current?
the rate at which charge passes through an area, such as the cross-sectional area of a wire.
What is the fundamental electric quantity?
Charge (Coulomb)
Units for current
1 ampere (A) = 1 coulomb/second (C/s).
__ is required to move charge between two nodes in a circuit
Work
What is electrical voltage?
Energy (in joules) per unit charge (1 coulomb) needed to move charge from one node to the other
Potential Difference
Voltage Units
1 volt (V) = 1 joules/coulomb (J/C)
What is a Reference node or Ground?
a specific, and usually clearly marked, node in
many circuits. Earth ground is always chosen as the
reference node because the earth’s potential is relatively stable and uniform due to its ability to store and distribute large quantities of charge.
The danger from electrical shock depends on:
- the amount of the shocking current through the body,
- the duration of the shocking current through the body,
- the path of the shocking current through the body.
Ideal voltage and current sources
“COME BACK”
Passive Convention
- Assign a current through each passive element in a circuit. The direction of each current be assumed arbitrarily
- Assign a voltage across the element such that assigned current through the element is directed from high to low potential
What is Electrical power? (units)
Current times Voltage (Joules per second; Watts (W))
Conservation of Energy in Circuits
- Requires that the total power associated with the circuit be zero
Positive power indicates that the element is either _ energy.
dissipating or storing
What is electrical Resistance?
When charge flows through a wire or circuit element, it encounters resistance
Electrical Resistance Equation
R = (ρ * l)/A
R = l / (σ * A)
* where ρ and σ are the material properties
resistivity and conductivity
Electrical Resistance Units
Ohms (Ω)
Ohms Law
The voltage across an ideal resistor is directly proportional to the current through it
V = R x i
In a series circuit…
- The current is the same everywhere
- V = V1 + V2 + V3 +…
- Equivalent Resistance = Req = R1 + R2 + R3 +…
In a parallel circuit…
- The volatge is the sane everywhere
- i = i1 + i2 + i3
- Equivalent Resistance = 1/Req = 1/R1 + 1/R2 + 1/R3 +…
Passive vs. Active Components
Passive:
* Resistor
* Capacitor
* Inductor
Active:
* Diode
* Transistor
Semiconductors
Silicon and germanium, from group IV of the periodic table whose conductivity is much weaker than that of a typical conductor but significantly stronger than that of a typical insulator.
Semiconductor devices: Transistor
- A three-terminal semiconductor device that can perform two functions that are fundamental to the design of electronic circuits: amplification and switching.
- Amplification consists of using an external power source to produce a scaled reproduction of a signal (linear).
- Switching consists of using a relatively small input current or voltage to control a larger output current or voltage (nonlinear)
Semiconductor devices: Diode
When sections of n- and p-type material are brought in contact to form a pn junction.
p-type
Semiconductors doped with acceptor elements: holes are the majority charge carriers, and free electrons are the minority charge carriers
n-type
semiconductors doped with donor elements: free electrons are the majority charge carriers, and holes are the minority charge carriers
