Components Flashcards
What does the symbol for a filament bulb look like?
a circle with an x
Why does the resistance decrease with temp/light intensity for thermistor and LDR?`
As higher temperature (caused by increase in current - the heating effect) means more charge carriers become available for conduction out-weighting the vibrations of ions within the lattice. This is because LDR and thermistor are both semi conductors.
Symbol for a thermistor?
a square with a line crossing through it at 45 degress but at one end becomes fully horizontal
Symbol for LDR?
a square surrounded by a circle with lines coming onto it at the top left corner
Symbol for a diode?
triangle with the spikey end coming onto a vertical line, all surrounded by a circle
Symbol for a LED diode?
The same as diode by has arrows coming off at the top right corner
What does forward bias mean for the diode?
the direction in which the current flows, reverse bias is the direction the current doesn’t flow (is very small)
What happens to the resistance as temp increases for a thermistor?
Decreases, as long as it it an NTC
What happens to the resistance as light intensity (LUX) increases for an LDR?
Decreases
What is a thermistor?
A resistor depending on temperature
How does resistance decrease for an LDR as LUX increases?
The light provides energy to release charge carriers increasing current and decreasing resistance
What are semi conductors used in?
Sensors
Is a diode a semiconductor?
YES
What usually is the threshold voltage for a diode?
about 0.6v
In a symbol for a cell which line represents the positive and negative terminal?
the longer one is positive
shorter one is negative
