Stocking Up on Electronic Parts

Electronics is no fun if you’re constantly driving to the store or paying extra shipping charges for all the bits and pieces for your circuits. It’s better to stock up on common parts and leave the special trips and online ordering for when you need something really special.

You—and the circuits you build—dictate which parts you should have on hand, but here’s a list to get you started. The minimum stock quantity indicates the number of components you ought to keep on hand.

Suggested Parts Stocking




Minimum Stock Quantity


1/8-watt standard values: 220 Ω, 330 Ω, 1 kΩ, 2.2 kΩ, 4.7 kΩ, 10 kΩ, 100 kΩ

6+ each


Linear taper 5 kΩ, 50 kΩ, 100 kΩ, 500 kΩ (miniature or other size okay, rotary pots preferred)

2 each

ceramic disc

.01 μF, .047 μF, .1 μF

6+ each


1 μF, 2.2 μF, 10 μF, 33 μF (all rated 25 volts or higher)

4 each


Mix of: 1N4001 (1-amp silicon), 1N5408 (3-amp silicon), 1N5822 (3-amp Schottky)

4 each

Signal transistors

2N2222 or 2N3904 NPN general-purpose



T1-3/4 or any preferred size, assortment of your favorite colors


Infrared phototransistor

OP999 or equivalent (T1-3/4 size, built-in IR filter; ones without the filter may be more susceptible to visible light)



Any available stock at reasonable price (when you get them, test their light and dark resistance values, and write down this information on a card; put the info card and component in a sandwich baggie)



Mix of: LM555 timer, LM386 audio amplifier, LM358 or LM741 op-amp (or similar)

2 each


Mix of:
• 22-gauge solid conductor (for breadboards)
• 12–14 stranded (for motors and batteries)
• 18–20 standard (for general purpose)
• 30-gauge wrap wire (for special-purpose wiring)

1 small spool or package each

For other components—switches, relays, inductors, zener diodes, power transistors, and so on—buy as you need. If you find you use a component more than others, feel free to add it to your stocking list.