AC/DC
- DC – Direct Current
- AC – Alternating Current – United States – 120v 60Hz
Wall outlet power AC current is easier to transport a waveform
Electronics use DC current because it is easier to produce a specific result
Digital circuits 1 and 0
Ohms Law – V=IR
- Voltage (V) Is the analog of water pressure
- Resistance (R) Describes the restriction of flow
- Current (I) Is the rate of flow volume/unit time
Ground
- Necessary for any circuit to work.
- Charge and Ground
- Ground is where electricity wants to be.
Kirchhoff’s Laws
Kirchhoff’s Law of Voltage (KVL)
The sum of voltages in a loop or circuit is zero.
Kirchhoff’s Law of Current (KCL)
The sum of current in and out of a node is zero.
Power
- P=IV
- P=I²R
- P=V²/R
A Resistor Capacitor (RC) Circuit
https://en.wikipedia.org/wiki/RC_circuit
Electronic Components
Schematics
| R | Resistor |
| C | Capacitor |
| L | Inductor |
| D | Diode |
| LED | Light-emitting diode |
| Q | Transistor |
| SW | Switch |
| IC | Integrated circui |
Capacitor
https://en.wikipedia.org/wiki/Capacitor
Measured in farads (symbol: F)
- 1 mF (millifarad, one thousandth (10−3) of a farad) = 1000 μF = 1000000 nF
- 1 μF (microfarad, one millionth (10−6) of a farad) = 0.000 001 F = 1000 nF = 1000000 pF
- 1 nF (nanofarad, one billionth (10−9) of a farad) = 0.001 μF = 1000 pF
- 1 pF (picofarad, one trillionth (10−12) of a farad)
Crystal Oscillators
https://en.wikipedia.org/wiki/Crystal_oscillator
Diode
https://en.wikipedia.org/wiki/Diode
Inductor
https://en.wikipedia.org/wiki/Inductor
An inductor, also called a coil, choke, or reactor, is a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it.
A light-emitting diode (LED)
https://en.wikipedia.org/wiki/Light-emitting_diode
Resistor
https://en.wikipedia.org/wiki/Resistor
Measured in ohms (symbol: Ω)
Resistors in series
R=R1+R2
Resistors in parallel
R = R1R2/R1+R2
Sensors
IR Receiver
Transistor
https://en.wikipedia.org/wiki/Transistor
A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power.
Mosfet
https://en.wikipedia.org/wiki/MOSFET
Photoresistor
https://en.wikipedia.org/wiki/Photoresistor
Potentiometer
https://en.wikipedia.org/wiki/Potentiometer
Surface Mount Package Sizes
| Metric | Imperial | Dimensions | Dimensions | Typical Resistor Power Rating (W) |
| 0201 | 008004 | 0.25 mm x 0.125 mm | 0.010 mm x 0.005 in |
|
| 03015 | 009005 | 0.3 mm x 0.15 mm | 0.012 in x 0.006 in | 0.02 |
| 0402 | 01005 | 0.4 mm × 0.2 mm | 0.0157 in × 0.0079 in | 0.031 |
| 0603 | 0201 | 0.6 mm × 0.3 mm | 0.024 in × 0.012 in | 0.05 |
| 1005 | 0402 | 1.0 mm × 0.5 mm | 0.039 in × 0.020 in | 0.1 or 0.062 |
| 1608 | 0603 | 1.6 mm × 0.8 mm | 0.063 in × 0.031 in | 0.1 |
| 2012 | 0805 | 2.0 mm × 1.25 mm | 0.079 in × 0.049 in | 0.125 |
| 2520 | 1008 | 2.5 mm × 2.0 mm | 0.098 in × 0.079 in | Typical inductor and ferrite bead package |
| 3216 | 1206 | 3.2 mm × 1.6 mm | 0.126 in × 0.063 in | 0.25 |
| 3225 | 1210 | 3.2 mm × 2.5 mm | 0.126 in × 0.098 in | 0.5 |
| 4516 | 1806 | 4.5 mm × 1.6 mm | 0.177 in × 0.063 in |
|
| 4532 | 1812 | 4.5 mm × 3.2 mm | 0.18 in × 0.13 in | 0.75 |
| 4564 | 1825 | 4.5 mm × 6.4 mm | 0.18 in × 0.25 in | 0.75 |
| 5025 | 2010 | 5.0 mm × 2.5 mm | 0.197 in × 0.098 in | 0.75 |
| 6332 | 2512 | 6.3 mm × 3.2 mm | 0.25 in × 0.13 in | 1 |
| 6863 | 2725 | 6.9 mm × 6.3 mm | 0.27 in × 0.25 in | 3 |
| 7451 | 2920 | 7.4 mm × 5.1 mm | 0.29 in × 0.20 in |
|
Surface mount technology (SMT) Used in Apple products
- 0201 Resistors
- 0201 Capacitors
- 0402 Resistors
- 0402 Capacitors
- 0603 Resistors
- 0603 Capacitors
Electronics Oven
Board Preheat: 260 Degrees Celsius for one hour
Solder Paste Properties
Common solder is an alloy from metals tin, silver, lead, and copper. The melting points of these metals are:
| Metal | Melting temperature |
| tin (Sn) | 232 °C |
| silver (Ag) | 961.8 °C |
| copper (Cu) | 1,084.6 °C |
| lead (Pb) | 327.5 °C |
| bismuth (Bi) | 271 °C |
The alloys, however, have lower melting temperatures than the pure metals:
| Alloy | Melting temperature |
| Sn63 Pb37 | 183 °C |
| Sn62 Pb36 Ag2 | 179 °C |
| Sn96.5 Ag3 Cu0.5 (SAC305) | 217–219 °C |
| Sn96 Ag4 | 221 °C |
| Sn92.5 Ag3.5 Cu1 Bi3 | 213 °C |
| Sn42 Bi58 | 138 °C |
For soldering with lead, the Sn63Pb37 alloy is almost universally used. For lead-free soldering, the alloy Sn96.5Ag3Cu0.5 is the most common. The alloy is also known as the abbreviation SAC305.
Profile Recommendations
The table below is a starting point for a profile for a batch oven. The optimal profile also depends on the PCB, and therefore the suitability of a profile must be verified with actual measurements.
| Zone | Lead (Sn63 Pb37) | Lead-free (SAC305) |
| Preheat | to 150 °C in 60 s | to 150 °C in 60 s |
| Soak | from 150 °C to 165 °C in 120 s | from 150 °C to 180 °C in 120 s |
| Reflow | Peak temperature 225 °C to 235 °C, hold for 20 s | Peak temperature 245 °C to 255 °C, hold for 15 s |
| Cooling | -4 °C/s or free-air cooling | -4 °C/s or free-air cooling |