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Typical Parts in a $50 Beginning Electronics Kit

Every lab, project, and MicroSim in this book was designed around a single box of parts that costs about $50. This appendix is that box, written out item by item: what goes in it, how many of each, roughly what it costs, and which chapter you will finally get to use it in.

Your Whole Toolbox on One Page

Volt waving welcome Fifty dollars. That's it. Everything you need to blink, buzz, sense, switch, and spin your way through this entire course fits in one small plastic box — and by the end you'll know every part in it by name. Let's light it up!

How to Read This List

Each table below uses the same four columns:

Column What It Tells You
Qty How many you want on hand for one student or one pair of students
Part The name to search for when you buy it
Typical Value or Spec The size, rating, or part number that works for this course
Where You Use It The first chapter or lab that needs it

Prices are approximate US prices for small online quantities and change constantly. Buying an assortment (a bag of 300 mixed resistors, a bag of 50 mixed LEDs) is almost always cheaper than buying single values.

Breadboard and Wiring

Qty Part Typical Value or Spec Where You Use It
1–2 Solderless breadboard 400 tie-point (half size) or 830 tie-point (full size) Chapter 6, Breadboard Lab
1 set Male-to-male jumper wires 65-piece pre-formed set, or 20 cm flexible wires Chapter 7
1 spool Solid-core hookup wire (optional) 22 AWG, for cutting custom-length jumpers Chapter 7

A solid-core wire is required for breadboards — stranded wire frays and will not push into a tie point. Keep a spare breadboard around; at roughly $2 each, a dead board is cheaper to replace than to debug.

Power

Qty Part Typical Value or Spec Where You Use It
1 MB102 breadboard power supply module 5 V / 3.3 V, plugs straight onto the power rails Chapter 5, Power Lab
1 7.5 V or 9 V wall adapter 5.5 × 2.5 mm barrel plug, to feed the module (avoid 12 V — see below) Chapter 5
5 PTC resettable fuse 500 mA hold / 1 A trip, in series with the +5 V rail Chapter 5
1 USB wall charger (alternative) 5 V, 500 mA or more Chapter 5
1 USB A male-to-male cable For the USB charger option Chapter 5
1 AA battery holder with leads 4 × AA, gives about 6 V Chapter 5
4 AA batteries Alkaline or rechargeable NiMH Chapter 5

Every circuit in this course runs on safe, low-voltage DC — 5 V from a module or charger, or about 6 V from batteries. Nothing in this kit ever touches wall voltage.

Why the Power Module Is Worth the Extra Two Dollars

For a classroom, the MB102 module is the recommended way to power a breadboard, and the reason is not convenience — it is what happens when a student shorts their circuit. Sooner or later one will, and something downstream takes the hit. When that something is a $2 module that unplugs from the power rails, you swap it in fifteen seconds and the student keeps building. When it is a wall charger, you have lost a more expensive part and possibly the rest of the class period.

Treat the module as a consumable. Buy a couple of spares up front and keep them in the same box as the breadboards.

Does the Module Have Overload Protection?

Partly. The AMS1117 regulator inside is genuinely protected — its datasheet specifies a 900 mA–1.5 A current limit and self-resetting thermal shutdown above 165 °C. But the board around it has no fuse, and the regulator survives a short by overheating rather than by interrupting anything: at 9 V in, a shorted rail asks it to dissipate about 10 W in a package rated for 1.2 W.

Two cheap changes fix this — use a 7.5 V or 9 V adapter rather than a 12 V one, and add a PTC resettable fuse to the + rail. Both are covered in full, with wiring schematics, on Safe Power for Learning.

Power it through the barrel jack, not the USB socket. The MB102's documented input is a 5.5 × 2.5 mm barrel jack wanting 6.5–12 V DC — pair it with a 7.5 V or 9 V wall adapter, or a 9 V battery clip ending in a barrel plug. The USB-A socket is not a reliable input: on some board revisions it feeds the regulator, on others it is an output for charging a phone, and even where USB input works, 5 V in for 5 V out leaves the regulator in dropout where it is barely regulating at all. Check what your board does before depending on it.

Never Wire to Wall Voltage

Volt pointing out a common mistake A USB charger is safe because it does the dangerous part inside its own sealed case. Your breadboard only ever sees the 5 volts that come out the other end. Never, ever wire a breadboard circuit to a wall outlet, an extension cord, or a lamp socket.

Resistors

Qty Part Typical Value or Spec Where You Use It
1 bag Resistor assortment ~300 pieces, 1/4 watt, 5% tolerance Chapter 9

A good assortment gives you at least 10 of each of these values, which covers every circuit in the book:

Value Color Bands Typical Job
100 Ω brown-black-brown LED current limiting on lower voltages
220 Ω red-red-brown The standard LED resistor in this course
330 Ω orange-orange-brown The other standard LED resistor
470 Ω yellow-violet-brown Dimmer LEDs, RGB LED channels
1 kΩ brown-black-red Transistor base resistor
2.2 kΩ red-red-red Transistor base resistor, dividers
4.7 kΩ yellow-violet-red Voltage dividers, 555 timing
10 kΩ brown-black-orange Pull-up and pull-down resistors, 555 timing
22 kΩ red-red-orange Slower 555 timing
47 kΩ yellow-violet-orange Slower 555 timing
100 kΩ brown-black-yellow Very slow RC timing
1 MΩ brown-black-green Long-delay RC circuits

Many pre-packed assortments skip 330 Ω and 2.2 kΩ. That is not a deal-breaker: a 220 Ω or a 470 Ω resistor will light every LED in this book, and a 2 kΩ substitutes for a 2.2 kΩ anywhere it appears. Check the value list before you buy, and top up the gaps for a few cents.

Buy the Big Bag

Volt offering a helpful tip A 300-piece resistor assortment costs about the same as 30 individually purchased resistors. Sort them into a labeled box the day you get them — future-you, halfway through a dark detector build, will be very grateful.

Capacitors

Qty Part Typical Value or Spec Where You Use It
10 Ceramic capacitor 0.01 µF (10 nF), marked 103 Chapter 10
10 Ceramic capacitor 0.1 µF (100 nF), marked 104 Chapter 14 (555 pin 5 bypass)
5 Electrolytic capacitor 1 µF, 16 V or higher Chapter 10
5 Electrolytic capacitor 10 µF, 16 V or higher RC Circuit Lab
5 Electrolytic capacitor 47 µF, 16 V or higher Chapter 10
5 Electrolytic capacitor 100 µF, 16 V or higher Chapter 22
2 Electrolytic capacitor 220 µF or 470 µF, 16 V or higher Chapter 22

Electrolytic capacitors are polarized — the stripe marks the negative lead, and installing one backwards can make it fail loudly. Ceramic capacitors have no polarity and go in either way.

Switches and Buttons

Qty Part Typical Value or Spec Where You Use It
10 Momentary push button (tactile switch) 6 mm × 6 mm, 4-pin, through-hole Chapter 16, Buttons Lab
2 Momentary push button with colored cap 12 mm, 4-pin, easier for small hands Chapter 16
2 Slide switch (SPDT) 3-pin, latching on/off Chapter 16
1 Toggle or rocker switch (optional) SPDT, for capstone project enclosures Chapter 26

Momentary push buttons are the single most-used input part in this book. You need plenty of them: the AND-logic lab and the OR-logic lab each use two at once, the combination-lock project uses four, and they are small enough to lose. Ten is the right number.

Why Four Pins for a Two-Wire Switch?

Volt thinking about a key concept A 4-pin tactile button really is just one switch. The two pins along the same side of the body are permanently wired together inside — the extra pair is there so the button sits down firmly and doesn't wobble. Pressing the button connects one side to the other side. The foolproof rule: use two pins that are diagonally opposite each other, and straddle the button across the center channel of the breadboard.

Variable Resistance and Sensors

Qty Part Typical Value or Spec Where You Use It
3 Trim potentiometer (trimpot) 10 kΩ, 3-pin, screwdriver-adjusted Dark Detector Lab
1 Panel potentiometer with knob 10 kΩ linear taper Chapter 11, LED Dimmer kit
1 Trim potentiometer 100 kΩ, for slow 555 timing Chapter 14
5 Photoresistor (LDR / photocell) 5 mm, roughly 5 kΩ lit to 1 MΩ dark Chapter 17
2 NTC thermistor 10 kΩ at 25 °C Chapter 11

Photoresistors and thermistors have no polarity and no brain inside them — they are simply resistors whose material responds to light or heat. That is what makes them the perfect first sensors in a course with no code.

Semiconductors

Qty Part Typical Value or Spec Where You Use It
10 NPN transistor BC547 Chapter 13, Transistors Lab
10 NPN transistor 2N2222 (or PN2222A) BC547 vs. 2N2222 Lab
5 PNP transistor 2N3906 Chapter 13
5 NPN transistor 2N3904 (a common BC547 substitute) Chapter 13
10 Small-signal diode 1N4148 Chapter 12
10 Rectifier / flyback diode 1N4007 Chapter 19 (motor protection)

The BC547 and the 2N2222 do the same job but have their pins in opposite order — the whole point of the comparison lab. Sort them into separate compartments and label both.

LEDs

Qty Part Typical Value or Spec Where You Use It
1 bag Assorted 5 mm LEDs ~50 pieces: red, green, yellow, blue, white Chapter 12, LED Circuit Lab
8+ Red 5 mm LEDs Diffused, for the shift register bar graph Chapter 15
2–4 RGB LED 5 mm, common cathode, 4 pins RGB LED Lab
1 LED "noodle" / filament LED (optional) 3 V flexible filament LED Noodle Lab

Blue and white LEDs need more forward voltage than red ones, so the same resistor gives you a dimmer result. Chapter 12 explains why.

Never accept a kit without RGB LEDs. One four-pin part that mixes any color you ask for is the single most memorable component in the whole box, and the color-mixing lab is one of the moments students remember months later. Many budget kits ship a single RGB LED, or none at all. If a kit you are considering leaves them out, either pick a different kit or buy a bag of ten separately — they cost only a few cents each, and having spares means students can keep one wired up while they experiment with another.

The Two Integrated Circuits

Qty Part Typical Value or Spec Where You Use It
2 555 timer IC NE555 or LM555, 8-pin DIP Chapter 14, LED Flasher
2 74HC595 shift register IC 16-pin DIP Chapter 15
2 8-pin DIP socket For the 555 Chapter 14
2 16-pin DIP socket For the 74HC595 Chapter 15

These are the only two chips in the course, and both are chosen because they can be fully understood without a microcontroller. Buy the DIP (through-hole) versions — surface-mount packages will not fit a breadboard.

Output Devices

Qty Part Typical Value or Spec Where You Use It
1 Active buzzer 5 V, beeps on its own when powered Chapter 19
1 Passive buzzer / piezo element 5 V, needs a signal to make tone Chapter 19
1–2 Small DC motor 3–6 V hobby motor with a paper propeller Chapter 18

Storage and Basic Tools

Qty Part Typical Value or Spec Where You Use It
1 Compartment storage box 18–24 compartments with a latching lid Day one
1 Small flat-blade screwdriver 2 mm, for trimpots and terminal blocks Chapter 11
1 Needle-nose pliers (optional) For bending and straightening leads Chapter 7

Approximate Budget

Category Approximate Cost
Breadboard and wiring $5
Power (MB102 module, 9 V adapter, battery holder) $7
Resistor assortment $5
Capacitor assortment $4
LEDs and RGB LEDs $4
Push buttons and switches $2.50
Potentiometers, photoresistors, thermistors $3.50
Transistors and diodes $5
555 timer, 74HC595, and DIP sockets $3
Buzzers and DC motor $4.50
Storage box and small tools $5.50
Total About $49

Buying pre-assembled "electronics starter kits" often beats this total — see Purchasing Component Kits for listings. Check the kit contents against this appendix before you buy, since some kits skip the 74HC595 or ship only two or three push buttons.

Cross-Check: A Real Off-the-Shelf Kit

To show what this looks like in practice, here is the WayinTop Electronics Component Fun Kit (part number WYTP-EC01), a widely sold starter kit that runs about $33 with free shipping. It is a good, honest match for this course — but not a complete one. Use this comparison as a template for evaluating whatever kit you find.

What It Already Covers

Course Requirement What the Kit Ships
Solderless breadboard Full-size (830-tie) breadboard
Jumper wires Three kinds: U-shape preformed, flexible, and 20-pin M-M / M-F / F-F ribbon
Momentary push buttons 10 mini tactile push buttons — exactly the quantity this course wants
Latching switch Slide switches
5 mm LEDs 50 total: 10 each of red, green, yellow, blue, white
RGB LED Included, but only one — buy a bag of spares (see below)
Resistors 10 each of 10 Ω, 100 Ω, 220 Ω, 470 Ω, 1 kΩ, 2 kΩ, 4.7 kΩ, 10 kΩ, 47 kΩ, 100 kΩ, 470 kΩ, 1 MΩ
Ceramic capacitors 0.1 µF ×10, 0.01 µF ×10, 220 pF ×10
Electrolytic capacitors 10 µF ×5, 100 µF ×5
NPN transistor 2N2222 ×3 and S8050 ×3
PNP transistor SS8550 ×3
Diodes 1N4148 and 1N4007
555 timer NE555
74HC595 shift register Included
Buzzers Both active and passive
Potentiometer One panel potentiometer with a shaft
Photoresistor and thermistor One of each
Power MB102 power supply module — the recommended module — plus a 9 V battery clip with a barrel plug
Perfboard Two boards, single- and double-sided

What You Still Need to Buy

Missing Part Why the Course Needs It Approx. Cost
RGB LEDs ×10, common cathode The kit ships only one, and the color-mixing lab deserves spares $2
Spare MB102 power modules ×2 The first student short-circuit costs you a module, not a class period $4
Small DC motor (3–6 V) Chapters 18 and 19 have no substitute for a spinning load $3
10 kΩ trim potentiometer ×3 The Dark Detector Lab calls for a screwdriver-adjusted trimpot, not a knob $2
BC547 transistors ×10 The BC547 vs. 2N2222 Lab compares two specific pinouts $2
330 Ω resistors ×10 Used throughout as an LED resistor (220 Ω or 470 Ω will substitute) $1
9 V wall adapter, 5.5 × 2.5 mm barrel plug To run the power module from the wall instead of a battery $5
Compartment storage box 200+ loose parts will not survive a school year in a bag $4
Small flat-blade screwdriver For the trimpots $1.50

At about $33 for the kit plus $24.50 in top-ups, you land at roughly $58 — a little over the target, but that includes ten RGB LEDs and two spare power modules, which are exactly the parts worth having extras of.

Use the Barrel Jack, Not the USB Socket

Volt pointing out a common mistake This one trips up almost everyone, because the USB socket does different things on different boards — on WayinTop's own diagram it is an output for charging a phone, while other MB102s accept power in through it. Skip the guessing: feed it 6.5–12 V through the round barrel jack, using the included 9 V battery clip or a 7.5–9 V wall adapter.

Extras You Can Ignore

This kit includes parts this course deliberately leaves out. None of them will hurt anything, but do not go looking for a lesson that uses them:

  • 1-digit and 4-digit 7-segment displays — interesting, but they really want a microcontroller to drive
  • 5 V relay — Chapter 19 explains how a relay works and notes it is not a kit part; if you have one, you now have a bonus demo
  • 4N35 optocoupler — not used in any lab in this course, and rarely useful in beginning STEM electronics generally; put it aside
  • Tilt switches and screw terminals — handy for capstone projects
  • Solder wire and pin headers — this kit is also sold as a soldering practice kit; none of the core labs require soldering, and any soldering should be adult-supervised

The kit is marketed "for Arduino, Raspberry Pi, ESP32, ESP8266," but no microcontroller is included — that is a description of what you could plug it into, and it makes no difference to this course.

Two Things to Verify on Arrival

Neither of these is stated in the listing, so check them when the box opens:

  1. Is the RGB LED common cathode or common anode? Lab 14 assumes common cathode. With a common-anode part, the wiring flips.
  2. Are the quantities per student or per class? Three transistors, one potentiometer, one photoresistor, and one thermistor is thin for a classroom. For a group of students, buy multiples of the sensors or a separate bulk bag.

Nice to Have, But Not Required

These are not counted in the $50 and are not needed to finish any core lesson:

Part Why You Might Want It Where It Appears
Digital multimeter Measuring voltage, resistance, and continuity yourself Chapter 20
Perfboard and headers Making a favorite circuit permanent Perf Boards Lab
7805 voltage regulator kit Building a fixed 5 V supply Chapter 22
Buck converter module Building an adjustable supply Chapter 22
XR2206 signal generator kit Generating waveforms Chapter 23
Small solar panel Solar night light capstone Chapter 23

Parts We Deliberately Left Out

Part of designing a good beginner kit is deciding what not to put in it. Every item below is genuinely useful in electronics, and every one of them would pull this course away from what makes it work: circuits a student can build, break, rewire, and understand in a single sitting, with no code.

Left Out Why
Microcontrollers (Arduino, Raspberry Pi Pico, ESP32) This course is deliberately code-free. They are the subject of the companion course, Learning MicroPython and Physical Computing.
7400-series logic gate chips (7400, 7402, 7408, 7432) You build AND, OR, and NOT gates out of buttons and transistors here. Pre-made gate chips would skip the whole lesson.
Flip-flop, counter, and decoder chips (74LS74, CD4017, CD4511) Sequential logic beyond a single RS latch belongs to the Digital Electronics course.
7-segment displays, LED matrices, and LCD modules These need either many more pins or a microcontroller driver to be interesting.
I2C and SPI sensor breakout boards A digital bus sensor cannot be read without code.
Servo motors A servo needs a timed pulse train from a microcontroller.
Relays and relay modules Chapter 19 explains how a relay works, but a transistor already covers every switching job in this kit.
Optocouplers / photocouplers (4N35, PC817) Never used in any lab in this course. Kits often include one; it will sit in the box unused.
Op-amps (LM358, LM741) Analog amplifier design is a course of its own.
Anything above 12 volts, or any mains-powered part Every lab here is safe, low-voltage DC.

You Know Every Part in the Box

Volt celebrating an achievement Here's something worth noticing, builder: there are fewer than thirty different parts on this whole page, and they are enough to build a night light, a logic gate, a flasher, and an eight-LED display. Knowing a small set of parts deeply beats owning a huge box you can't explain — and that's your superpower in action!