Work Package 3 Flashcards
how does an LDR work?
the resistance changes according to the amount of light shining directly on it.
in darkness, what happens to an LDR resistor?
in darkness, its resistance rises to about 10M
in bright light, what happens to an LDR resistor?
in bright light, its resistance falls to about 1 K
are LDRs polar or non-polar?
non-polar
if the Vout is high and light intensity increases, what happens to the Vout?
the Vout changes from high to low
if the Vout is low and light intensity decreases, what happens to the Vout?
the Vout changes from low to high
what is Vout?
voltage out
how does a thermistor work?
its resistance changes according to temperature. It converts changes in temperature into changes in electric current.
what is the most popular type of thermistor?
the negative coefficient type. Its resistance decreases as it gets hotter
are thermistors polar or non-polar?
non-polar
if the Vout is high and the temperature increases, what happens to the Vout?
the Vout changes from high to low.
if the Vout is low and the temperature decreases, what happens to the Vout?
the Vout changes from low to high
what is a PIC controller also called?
a computer in a chip
what can a PIC controller be programmed to do?
to respond to input devices and control output devices.
when PIC microcontrollers run programmes, what voltages do they run them between?
3V and 5.5V d.c.
what is a voltage regulator?
electricity regulation device designed to automatically convert voltage into a lower, usually direct current (DC), constant voltage.
what are the 6 different sized PICAXE PIC microcontrollers?
- 8 pin
- 14 pin
- 18 pin
- 20 pin
- 28 pin
- 40 pin
what are two facilities that PICAXE microcontrollers have built into them?
- analogue to digital conversion (ADC)
2. infra-red
what does a flowchart show?
the order in which a series of commands are carried out
what are the two states of digital signals?
- high, which equals 1
2. low, which equals 0, therefore it cant use the decimal system of counting, which uses 10 digits.
what is a binary system?
a system in which information can be expressed by combinations of the digits 0 and 1
what is a bit and what is a byte?
a bit is the binary digits 0 and 1. Eight bits make one byte.
what does MSB and LSB stand for?
MSB - most significant bit
LSB - least significant bit
what does the sensor in an analogue system do?
the sensor generates a voltage which then controls something. E.g. a heating system.
