electrical currents Flashcards
What is conventional current
-is the direction of current from positive to negative
How many electrical path in a series circuit
-one
What is a series circuit
-When the positive pole of one cell touches the negative pole of another cell it is connected in series
What happens when a resistor is added in a series circuit
-Total current in the circuit decreases
What happens if there is more cells in a circuit
-the stronger the current and brighter the bulb
What is a parallel circuit
- the circuit branches and the current divides
- the total of current not flow through
What happens if you add more resistors in a parrel circuit
-total resistance in a circuit decreases
What happens if you connect a LED in a certain way
-it conducts electricity and emits red, green and yellow light
What do LED do these days
-also emites ultra violet and infrared light
What is a photocell
-also a LED but it operates in reverse
What does a photocell do
-it absorbs light, the absorbed light energy cause an electric current
What happens if it is connected to an external appliance
- it supplies electrical energy
eg. is a solar powered calculator
How does a alternating current (doorbell) work
- has electromagnet that vibrates a 60 Hz. The copper turning around the soft iron core forms an electromagnet which is connected to the alternating current supplyof the house
- as soon as the current changes direction, the magnet attracts and repels the metal knocker, which causes the buzzing sound
What is a direct current
- a doorbell that makes ding dong
- the copper turning around the soft iron core form an electromagnet and are attached to the battery. If the switch is pushed, it switches the current on and off
- the metal knocker is then attracted by the electromagnet for a moment, which breaks the circuit,causing the distinctive bell sound
