Parts (Electronics)

IC

Part	Name	Cost	Notes
555/556	Timer	$2.15 / 50
LM741	Op Amp	$1.20 / 10
LM317	Linear reg.	$1.30 / 10
LM78xx	Linear reg.	$1.30 / 10	The xx is the voltage; 05,06,08,10,12,15,18,24

Microcontrollers

Name	Cost	I/O	Flash	Speed	Peripherals	Notes
ATTINY85	60¢	6	8K	2pwm, 2-8 timer, 1adc	20MHz	Small dev boards are available for around $1.75
ATMEGA8	90¢	23	8K	16MHz	3pwm, 2adc, 2-8/1-16 timer	Small dev boards are available for around $1.75

Modules

Name	Cost	Description
Voltage Meter	$2.00	3x7seg LED, generally wide ranges of voltages
Buck Module	$2.50	(4-40v) → (1.3-37v) @ 2A; includes led panel. Found a 9A version for $5, no display.

Semiconductors

Part	Cost	Limit	Part
PNP BJT (TO-92)	$1.43 / 100	40v 200mA	2N3906
NPN BJT (TO-92)	$1.20 / 100	60v 200mA
NPN BJT (TO-92)	$1.20 / 100	60v 200mA

Packages

Name	Description
TO-92	Small black, semi circle, 3 leads from the bottom
DIP	dual in-line pin, pins are 1/10" apart, 1/4" wide
TO-3	metal can, good for heat dissipation, cheap heat-sinks, shaped like a rounded diamond about 1"x1.5", leads are .43" apart
TO-220	metal tab heatsink

TO stands for transistor-outline.

Linear Components

Resistors

Resistors are typically 1/4W. The cost for these is negligible, assortment packages typically come in around 0.6¢ per resistor. To handle higher wattage, they can be used in parallel.

Capacitors

Electrolytic up to 220uF are very cheap (2.8¢) and available in assortment packs. Up to 2200uf is still pretty cheap, 7.5¢ with a 1000uF@10v cap coming in around 5.6¢. Beyond this, the goes up rapidly for either additional capacitance or voltage with a 2200uF@25v around 50¢.

Ceramics are cheap up to 100nf, also available in assortment packs (0.4¢).

Inductors

Small inductors are fairly cheap; assortment packs of 1/2w from 1uH to 4.7mH 5.5¢ a piece. They look like resistors.