Vocabulary
What is a circuit
a closed, conductive loop that allows electricity (electrons) to flow from a power source
What are the 2 types of closed direct current circuits?
Series and Parallel
What is the unit for current?
Amp
What is the unit for Power?
Watt?!
What is the unit for Resistance?
Ohm
What is the law that relates voltage, current, and resistance?
Ohms Law
Name one power source for a house
electric grid, solar panels
Current is the rate of...
charge per time
A device uses 120 V and consumes 240 W. Find its resistance.
60 ohms
Resistance depends on length, cross-sectional area, and this property.
Resistivity
Compare and contrast DC and AC circuits
Direct-current flows in one direction
Alternating-current alternates direction
A 12 V battery is connected to two resistors in series: 3 Ω and 9 Ω. Find the current and the voltage across the 9 Ω resistor.
1 A; 9 V
If 10 C of charge passes a point in 2 seconds, the current is:
5 A
How do we relate electrical power to energy?
Power is energy divided by time
Explain an RC Circuit
Energy is stored and released as a function of time
Voltage is best described as this between two points.
Electric Potential Difference
A 10 Ω resistor is in series with a parallel combination of 6 Ω and 3 Ω. Total voltage is 20 V. Find total current.
1.7 A
If a resistor has a resistance of 50k-ohms and a time constant of 0.2 seconds, what is the capacitance?
4muF
A circuit dissipates 100 W at 10 A. Find voltage and resistance.
10 V and 1 ohm
A 2 kΩ resistor and 5 μF capacitor are connected. Find the time constant.
0.01 s
Explain the difference between watts and Kwh
Watts is power and Kwh is energy
Which circuit (series or parallel) is used in homes and why?
parallel, so devices get full voltage and work independently
In an RC charging circuit, Battery = 3 V, R = 2 kΩ, C = 100 μF
Write the equation for current as a function of time
i(t)=.00015e-t/.2
A resistor’s power doubles. If resistance stays constant, what happens to current?
sqrt 2
Find the equivalent resistant when a 2 and 4 ohm resistor are in a parallel circuit with each other and in series with a 6 ohm resistor.
7.33 ohms