Chapter 10: DC Circuits Flashcards
What does DC mean?
DC = direct current
The current does not change with time and travels in one direction only. Used for small electronics devices, such as a phone, computer, etc.
DC is supplied by batteries and solar panels. To convert to AC for use in on home appliances, solar panels use an inverter.
Wall sockets provide AC current, so it must be converted into DC current before you can use it in a DC device by a rectifier.
What does AC mean?
AC = alternating current
The current changes with time like a sine wave, 60 times per second (60 Hz) and changes direction with each cycle. AC is used to power large appliances in the home, such as washing machines.
AC is supplied by wall sockets and power stations for towns and cities.
What does a multimeter measure?
Multimeters can measure voltage (V), resistance (R), and sometimes current (I).
What is the function of a battery in a circuit?
A battery provides a potential difference (voltage). By moving charges through the potential difference, they gain electrical potential energy, which they then transfer to other elements in a circuit.
What causes electrons to move through a wire (electricity)?
A voltage difference - more positive charges at one end of a wire and more negative charges at the other end create an electric field E, and the charged electron q experiences a force F = qE and accelerates as a result.
How doe an incandescent light bulb work?
Electrons moving through the wires collide with atoms in the bulb filament, which has a much higher resistance than the wires, and transfer electric potential energy to the atoms in the filament. As a result, the atoms move around more, heat up, and eventually heat up to the point where they are producing visible light.
Why are incandescent bulbs inefficient?
Incandescent bulbs create more infrared (heat) radiation than visible light, which is wasted energy.
What kind of light bulbs are more efficient than incandescent light bulbs?
Fluorescent (including compact fluorescent) and LEDs (light-emitting diodes).
Do resistors in series have the same current or the same voltage?
Resistors in series have the same current.
Do resistors in parallel have the same current or the same voltage?
Resistors in parallel have the same voltage.
Two resistors have the same current. Are they are series or parallel with each other?
They are in series.
Two resistors have the same voltage. Are they are in series or in parallel with each other?
They are in parallel.
What is Kirchoff’s Junction Rule?
All current entering a junction leaves a junction.
What is Kirchoff’s Loop Rule?
The sum of the voltage drops across each component in a loop add to zero.
Do resistor branches in parallel have the same current or the same voltage?
Resistor branches in series have the same voltage.
