Electronics for Physical Computing Materials: capacitor, diode, LED, transistor, switch,resistor, relay, proto board, multimeter

Electrical Energy

Current Current is a measure of the magnitude of the flow of electrons in a circuit. It is measured in Amperes, or Amps. How much energy is Available.

Voltage Voltage is a measure of the electrical energy of a circuit. It is measured in Volts. The quality of energy

AC vs. DC In a DC circuit, current always flows one direction. In an AC circuit, poles of the circuit are reversed in a regular repeating cycle. Most of our circuits will be DC

Conductors Low resistance pathways for electrical current to follow.

Insulators Keep electrical current from passing through.

Circuit Board Insulating and conductive “road map” for electricity Holds electrical components

Resistors The resistor can be defined by it's main purpose, a device to control or limit the flow of current, hence we can say that the main parameter of a resistor is it's resistance, which is measured in Ohm's (). they can also be used as voltage dividers to generate very precise voltages out of bigger voltages.

Reading a Resistor

OHM’s Law V = voltage I = current R = resistance Ohm’s law shows how V, I and R are related

Using Ohm’s Law Find voltage If you know current and resistance, you can find voltage from V = I R. For example, if the current I = 0.2A and the resistance R = 1000 ohms, then V = 0.2A * 1000 Ω = 200V Find current If you know voltage and resistance, you can use algebra to change the equation to I = V / R to find the current. For example, if V = 110V and R = ohms, then I = 110V / Ω = 0.005A Find resistance If you know voltage and current, you can use algebra to change the equation to R = V / I to find the resistance. If V = 220V and I = 5A, then R = 220V / 5A = 44 Ω

Watts W= V x A We won’t be using watts

Variable Resistors Potentiometers Photoresistors Force sensitive resistors (FSR) Flex sensors Thermistors All change resistance

Capacitors store up electricity while current is flowing into them, then release the energy when the incoming current is removed

Diodes Diodes permit the flow of electricity in one direction, and block it in the other direction. Because of this, they can only be placed in a circuit in one direction.

LED Light Emiting Diode (LED’s) are special types of diodes which emit light when current flows through them

Switch control the flow of current through a junction in a circuit:

Transitors and Relays switching devices allowing control and amplification.

Parallel vs. series parallel series

Series When resistors are in series, the voltage drops across each resistor, and the total resistance is equal to the sum of all the resistors. We know the voltage drops across each resistor, and we know that the total of all the voltage drops equals the voltage across the battery. So Vin = V1 + V2.

Parallel For resistors in parallel, the voltage across them is equal, but the current is divided between them. The total current is constant, however, so we know that the divided current across the parallel resistors is equal to the total current. So I1 + I2 = Itotal.

Breadboard, Prototyping board

Arduino setup Computer w/Arduino IDE Computer w/Arduino IDE usb Programmed and powered through USB cable. Program will “live” on Arduino even when powered off

Homework: What value would a orange- red- brown coded resistor be?