Resistors Flashcards
What do resistors do?
Resistors limit the flow of electrical current and divide voltage in circuit.
How do resistors work?
They use a resistive material to convert electrical energy into heat, opposing the flow of current.
What are the main types of resistors?
Fixed resistors, variable resistors, and special-purpose resistors.
What is a fixed resistor?
A resistor with a constant resistance value that cannot be adjusted.
What is a variable resistor?
A resistor whose resistance can be manually adjusted, such as a potentiometer or rheostat.
What are common materials used in resistors?
Carbon film, metal film, wire-wound, and ceramic.
What is the resistance value of a resistor measured in?
Ohms (Ω)
What is the power rating of a resistor?
The maximum power a resistor can dissipate without damage, measured in watts (W).
What is a carbon film resistor?
A resistor made by depositing a thin layer of carbon on a ceramic substrate, used in general-purpose applications.
What is a metal film resistor?
A resistor with a thin metal layer, offering higher precision and stability than carbon film resistors.
What is a wire-wound resistor?
A resistor made by winding a resistive wire around a ceramic core, used for high-power applications.
What is a ceramic resistor?
A high-power resistor made from a ceramic composite, often used in industrial applications.
What is a thermistor?
A resistor whose resistance changes significantly with temperature, used for temperature sensing or compensation.
What is an LDR (Light-Dependent Resistor)?
A resistor whose resistance decreases as light intensity increases, used in light sensors.
What is a resistor network?A
A package containing multiple resistors, often used in compact circuits for common resistance needs.
How do you calculate total resistance in series?
Add the resistance values.
How do you calculate total resistance in parallel?
Use the formula
1 = 1 + 1
RT R1 R2
What is the color code on resistors used for?
To indicate the resistance value, tolerance, and sometimes temperature coefficient.
What is the tolerance of a resistor?
The percentage by which the actual resistance can vary from its nominal value.
What are typical resistor tolerances?
±1%, ±5%, and ±10%
How do resistors affect circuit performance?
They control current flow, set voltage levels, and dissipate power.
What is a pull-up resistor?
A resistor used to ensure a default high logic level in digital circuits.
What is a pull-down resistor?
A resistor used to ensure a default low logic level in digital circuits.
What can go wrong with resistors?
Overheating, value drift, or complete failure due to excessive current or voltage.
How do you test a resistor?
Use a multimeter to measure its resistance and compare it to the specified value.
What is a precision resistor?
A resistor with a very low tolerance, used in applications requiring high accuracy.
What is a current-sensing resistor?
A low-value resistor used to measure current by detecting voltage drop across it.
What is a fusible resistor?
A resistor that acts as a fuse, breaking the circuit if the current exceeds a safe level.
What is the purpose of a voltage divider circuit?
To reduce voltage to desired level using two or more resistors in series.
How do you ensure a resistor is used within its limits?
Verify the resistance value, power rating, and tolerance against the circuit’s requirements.
