Electronics for Artists
class # 1
electricity basics, tools, basic circuits
electricity!
goals
• electricity basics
• how to use a multimeter
• introduction to prototyping
• how to read schematics
• series and parallel circuits
Grand Theory!
• electrons want to go from a place of high
voltage to a place of lower voltage.
• put hoops in their way and we can make the
electrons do tricks for us!
High Voltage
Electron
Not so high voltage
Everything all at once
• current is the flow of electrons.
• voltage is the force that pushes the current.
• resistance is anything that resists the
current.
• ground is where the current flows to.
• conductor is what the current flows
through.
Everything not at once
Current
1) Current is the flow of electrons through a conductor or
semiconductor.
2) Current is measured in Amperes or Amps.
3) The symbol for Amps is I.
4) Some materials conduct current better than others.
These are known as conductors, semiconductors, and
insulators.
5) Current flow is from positive to negative. Sort of.
6) Current flow requires an imbalance of charge between
two points.
Voltage
1) Voltage is the difference in charge between two
points.
2) Voltage is measured in Volts.
3) The symbol for Volts is V.
4) A voltage does not exist in isolation. (see 1)
Power
• Power is the amount of work that can be
done
• Measured in watts
• Watts = Amps x Volts. Easy!
Resistance
1) Resistance is whatever resists the flow of current.
2) Resistance is measured in Ohms.
3) The symbol for Ohms is R.
4) All materials have varying degrees of resistance,
depending on strength of electron bonds.
Ground
1) Zero voltage reference level. Think of it as the sea
level of voltage.
2) Relative to the circuit it’s connected to.
Conductor
1) Conductors pass current with very low resistance.
Metals are good conductors.
2) Pass too much current through a conductor and bad
(exciting?) things happen. More about that later.
2) Semi-conductors pass current under special
conditions. They are magical and will be talked about
later with great enthusiasm.
6) Insulators have a very high resistance and will not
pass current. Glass and rubber are two typical insulators.
how to succeed at
electronics
1) Document your process
2) Expect things to go wrong
3) Help each other
4) The internet knows everything
Shopping
• Radio Shack - Everywhere
• All Electronics - Van Nueys
• Jameco, Digikey - Online
Books
Circuit
1) A working circuit must have a closed loop of current flow
through a load.
2) All circuits contain voltage, current, and resistance.
3) A circuit with a break in it is called an open circuit.
4) Open circuits are really boring.
5) A circuit without enough resistance in its load is called a
short circuit.
6) Short circuits are bad.
Ohms law
1) Every circuit has Voltage, Current and Resistance.
2) V=IR. Voltage = Current * Resistance.
3) I=V/R. Current = Voltage/Resistance.
4) R=V/I. Resistance = Voltage/Current.
5) We will use this on occasion.
Kirchoff’s law
•
•
Current in = Current out (shorter version)
•
Iin = Iout (shortest version)
The sum of a current entering a junction equals
the sum of the current exiting a junction.
(longer version)
schematics
1) Circuits are represented by schematics.
2) Functionally identical circuits can often be
drawn multiple ways.
Series Circuit
Series
1) All components are connected end to end.
2) Single path for electrons to flow - all components share the
same current.
3) Total resistance of circuit is equal to sum of individual
resistances.
4) Total voltage in circuit is equal to sum of individual voltage
drops.
5) Multimeters measure current in series with circuits.
Calculating Series Resistance
Rt = R1 + R2 + R3+...Rn
Parallel
Parallel
1) The same voltage exists across each branch and is
equal to source voltage.
2) The current through each branch is inversely
proportional to the resistance of that branch (lazy
electrons take the easy way)
3) Total resistance of circuit is less than the sum of
individual resistances. (more paths to travel)
4) Total current in circuit is equal to sum of individual
branch currents. (Kirchoff’s law)
5) Multimeters measure voltage in parallel with circuits.
Calculating Parallel Resistance
recess!
Battery
Battery
1) Converts chemical energy into electrical energy.
2) Batteries are either primary (non-rechargeable) or
secondary (rechargeable).
3) Rated in Amp Hours.
4) Batteries in series multiply voltage.
4) Batteries in parallel multiply capacity (amount of
current they can supply).
Breadboard
1) Temporary assembly board.
2) Conductive paths hidden below sockets.
3) Sockets contain metal sleeve which connect
components to conductive paths.
Breadboard
wire
1) Provides low resistance path for current.
2) Protected by insulated coating.
3) The smaller the wire, the less current it can handle before
melting.
wire
1) Diameter is expressed as gauge.
2) Large gauge = small wire. Small gauge = large wire.
Sorry about that.
3) In lab we will use 22 gauge solid wire, which fits nicely
into the breadboards. 22 gauge wire is rated for 2 amps.
4) Solid wire will break when fatigued and can't carry as
much current as stranded wire.
5) Stranded wire is preferred for permanent circuits, as it's
more flexible and can carry more current.
This is a drawing of wire
Resistor
1) Conductive material that impedes current flow.
2) Converts electrical energy into heat energy.
3) Typical power rating of 1/4 to 2 watts.
4) Uses color bands to specify resistance.
Resistor
Multimeter
• measures current, voltage, resistance and
continuity
• allows you to “see” what’s happening
Lab 1
• series circuit using 1k resistors
• measure current, voltage drops
• switch to 100k resistors - does the current
change? do the voltage drops change?
Lab 2
• parallel circuit using 1k resistors
• measure voltage drop
• measure current through each leg
• measure total current
• switch to 100k resistors - does current
change? how about voltage drop
led
1) Converts electrical energy into light.
2) Works in one direction only.
3) Current flows from anode to cathode.
4) Short things are closer to the ground.
5) Requires nominal .6v to conduct.
led
switch
1) Mechanical device that interrupts current flow.
2) Characterized by number of poles and number of
throws.
Lab 3
• LED circuit with switch
Next week
• Soldering
• AC
•
transformations
• resistance - electricity into heat
• capacitance - electricity into a charge field
• induction - electricity into magnetic field