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Components

Components

Voltage: difference in electronic charge between two points
Amperage: rate at which electrons flow past a point in a circuit.
Resistance: amount a component resists the flow of electrical energy

Resistor

  • Reduces voltage

Transistors

  • Electronic switch
    • If voltage applied to the base then flow can go through the resistor
      How they work

Inductor

In AC Current:
- Stores charge in Magnetic Field
- Resists changes in current
- Rounds the edges of squarewave current.

In DC Current:
- Resists Changes in Voltage from off to on
- This is because the energy gets put into a magnetic field

Capacitor

  • Store energy in form of static charge
  • Resist changes in voltage
  • Larger caps (100uF) store more energy but react slower to changes
  • Smaller caps (0.1uF) sore less energy but are fast to react to changes

Electrolytic Capacitors: Are polarized and have a positive and a negative pin. These are the big Cylinder Components. Can be almost any Capacitance.

Ceramic Capacitors: Are non-polarized and can be plugged in on any terminal. But have small amount of Capacitance.

Film Capacitors:

Decoupling capacitor

  • Reduce Noise from another part of the circuit.
    • On Voltage Spikes
    • On High Current Demand
    • A UPS for the power supply
  • Choose a Capacitor that is rated 20% higher than the voltage that will go though the wire.
  • Capacitor is placed from Main Voltage to ground

Charge Pump

  • Uses Capacitors to raise or lower voltage to be used in a circuit

Relay

  • Electronic Switch
  • Is on when powered.
  • Is off when not.

Latching Relay

  • Electronic Switch
  • When first receives power changes state to on
  • When power is removed is still on.
  • When reset pin is powered then reset back to off.

Transformer

  • Takes AC power and steps down voltage or step up.
  • Creates a EM field around the Iron block due to the changes in Alternating Current

Depending on the number of turns of the wire on the input and output connection it will step up or down the voltage.

\[ \dfrac{\texttt{Voltage\_2}}{\texttt{Voltage\_1}} = \dfrac{\texttt{Turns\_2}}{\texttt{Turns\_1}} \]

Step-down Transformer Example:
- Primary coil has 1,200 turns and is connected to 240V AC.
- Secondary coil has 10 turns and outputs to 2V AC.

Step-up Transformer Example:
- Primary coil has 1,000 turns and is connected to 200V AC.
- Secondary coil has 10,000 turns and outputs to 2,000V AC.

Voltage Regulator Module (VRM)

  • Keeps the Voltage static preventing overvolting from a wall converter.
    • Uses MOSFETS as the switches
  • Since this circut's voltage is a small saw tooth with the median being the expected voltage there are some fluctuations
    • By adding more of these VRMs in parallel they even out the discrepancies making the voltage more stable

Circuit Diagram:

Source

Diode

  • Makes sure current can only flow in one direction.
    • Blocks current flowing in the other direction.
  • Anode is the Arrow part on the Schematic and plugged in to the positive terminal

Light Emitting Diode (LED)

  • Most LEDs have 20mA max Current
    • Must use a resistor to prevent Overvoltage.
    • Resistor can be before or after the LED

Positive Temperature coefficient (PTC)

  • Is also called a thermistor
  • Will increase resistance as current flows through it
    • Acts as a resettable fuse
    • If there is a short in the circuit then there will be more current which increases the resistance which prevents the circuit from working.
    • Great when accidentally plugging the leads in wrong.

Resonators and Oscillators

  • Used as a timing mechanism
  • Resonators are lower frequencies then oscillators

Projects that use RF and Serial Communication will need a better timing mechanism than the internal oscillator

Internal Oscillator

  • The least precise but is embedded in the chip

External Oscillator

  • Most expensive but is has the best precision and tolerance

Crystal Resonator

  • Uses mechanical resonance of a vibrating piezoelectric crystal to create an electrical signal with a precise frequency.
  • Inexpensive compared to oscillator

Ceramic Resonator

  • Cheaper than crystals but less precise
  • Are 10 times more accurate than the internal oscillator

MOSFETs

  • Used to switch DC Circuits

Triac

  • Used to switch AC Circuits