Source: https://fullstackelectronics.com/the-parts

# The Parts

What to buy, how many, and when you'll need it.

You can buy the parts in stages. Start with the breadboard components for Stages One to Three. Choose the surface-mount parts when you reach PCB design in Stage Four. Each experiment shows you how to identify and connect the parts it introduces.

The tables separate the quantities you use from suggested purchases with spares. The supplier links are examples from Mouser. If you buy elsewhere, check the full part number, package and pinout against the experiment. A similar name or appearance does not guarantee a suitable replacement.

To start Experiment 1, you need one NE555 in an 8-pin DIP package, two 10 kΩ resistors, one 10 µF electrolytic capacitor and one 10 nF ceramic capacitor. You also need one red LED, one 220 Ω resistor, and the breadboard, wire and instruments listed in [The Bench](https://fullstackelectronics.com/the-bench.html.md).

You can leave the rest until you need it. The schedule below shows when to have each new part ready.

## When to buy

- Before Experiment 1: the starter parts above. Buy spares now if you want to avoid a second order for the same values.
- Before Experiment 2: the LM393, the CD4001B, two 2N3904 transistors, three 4.7 kΩ divider resistors, and four 10 kΩ resistors for the pull-ups and base resistors. Add a second set of timing parts (two 10 kΩ and a 10 µF), an LED and a 220 Ω resistor.
- Before Experiments 3–6: 1 kΩ resistors for Experiment 3, and 4.7 kΩ resistors for the collector loads and the optional divider in Experiment 4. Add a 2.2 kΩ for Experiment 5 and 2N3906 transistors for Experiment 6.
- Before Experiments 7 and 8: no new part types. Experiment 7 takes one 2N3906, one 4.7 kΩ and three 10 kΩ for the divider on the board. Experiment 8 takes four 2N3906, three 2N3904 and two 4.7 kΩ.
- Before Experiments 9–13: a 1 µF ceramic capacitor for Experiment 9, the remaining breadboard parts for the complete timer in Experiment 12, and a 100 kΩ resistor for Experiment 13.
- During Stage Four: choose components when you assign footprints in Experiment 17. Have samples ready for the printed layout check in Experiment 19, then order the PCBs after the design checks. Have the full assembly quantities ready for Experiment 20.

## Breadboard components · Stages One to Three

The Needed column lets you keep the chip and IC timers assembled while you build the transistor timer on the third breadboard. You can reuse the parts that you remove as you improve that third build. The Suggested buy column includes spares, and extra transistors and divider resistors to measure and compare.

### Semiconductors

| Part and package | Needed | Suggested buy | First experiment | Example supplier |
|----|----|----|----|----|
| 2N3904 (NPN, TO-92) | 18 | 50 | 2 | [512-2N3904BU](https://www.mouser.com/en/ProductDetail/onsemi/2N3904BU?qs=or4AE2qAS%252Bd0Jdpn%2F8ktKg%3D%3D) |
| 2N3906 (PNP, TO-92) | 7 | 20 | 6 | [512-2N3906BU](https://www.mouser.com/en/ProductDetail/onsemi/2N3906BU?qs=iN0KuJO79Kbn9o7a2lB4uA%3D%3D) |
| NE555 (8-pin DIP) | 1 | 2 | 1 | [595-NE555P](https://www.mouser.com/en/ProductDetail/Texas-Instruments/NE555P?qs=rkhjVJ6%2F3EIf4CWgjIKuKQ%3D%3D) |
| LM393 (dual comparator, 8-pin DIP) | 1 | 2 | 2 | [595-LM393P](https://www.mouser.com/en/ProductDetail/Texas-Instruments/LM393P?qs=1K8%2FAQHn5WT5g4otW1rg%2Fg%3D%3D) |
| CD4001B (quad NOR gate, 14-pin DIP) | 1 | 2 | 2 | [595-CD4001BE](https://www.mouser.com/en/ProductDetail/Texas-Instruments/CD4001BE?qs=Tv815z3GeNSKspfG7F34rg%3D%3D) |
| Red LED, 5 mm | 3 | 10 | 1 | [604-WP7113ID](https://www.mouser.com/en/ProductDetail/Kingbright/WP7113ID?qs=hyavMCx%252BcmDJhCThgY7pfQ%3D%3D) |

The complete transistor timer uses 16 NPN and 7 PNP transistors. Two more NPN transistors stay in the IC timer, so you need 18 in total.

Even transistors with the same part number vary slightly. Experiment 4 shows how much that matters when two of them share one current. Buy each transistor type from one manufacturer.

### Resistors · ¼ W through-hole

| Value | Needed | Suggested buy | First experiment | Example supplier |
|----|----|----|----|----|
| 10 kΩ | 20 | 50 | 1 | [603-CFR-25JB-52-10K](https://www.mouser.com/en/ProductDetail/YAGEO/CFR-25JB-52-10K?qs=oypCK0zG32646UD7yHncYg%3D%3D) |
| 1 kΩ | 2 | 10 | 3 | [603-CFR-25JB-1K0](https://www.mouser.com/en/ProductDetail/YAGEO/CFR-25JB-1K0?qs=50q%252BZR8McTFNhjnln8KDLg%3D%3D) |
| 4.7 kΩ | 10 | 20 | 2 | [603-CFR-25JB-52-4K7](https://www.mouser.com/en/ProductDetail/YAGEO/CFR-25JB-52-4K7?qs=oypCK0zG3252T%2FvSUvCH9g%3D%3D) |
| 2.2 kΩ | 1 | 5 | 5 | [603-CFR-25JB-52-2K2](https://www.mouser.com/en/ProductDetail/YAGEO/CFR-25JB-52-2K2?qs=oypCK0zG327VTyS4ZTRfWw%3D%3D) |
| 100 kΩ | 1 | 5 | 13 | [603-CFR-25JR-52100K](https://www.mouser.com/en/ProductDetail/YAGEO/CFR-25JR-52-100K?qs=KUIzHt%2Fe91lllFJEWbd6ag%3D%3D) |
| 220 Ω | 3 | 10 | 1 | [603-CFR-25JB-52-220R](https://www.mouser.com/en/ProductDetail/YAGEO/CFR-25JB-52-220R?qs=2kOmHSv6VfSGEghFCEk%2FPQ%3D%3D) |

The IC timer and the PCB each take their divider from three 4.7 kΩ resistors. The transistor breadboard build makes its divider from three 10 kΩ resistors in Experiment 7. The 4.7 kΩ breadboard quantity covers three for the IC divider, three for the optional divider in Experiment 4 and four for the transistor comparators.

A resistor assortment also works if it contains the listed values in enough quantity.

### Capacitors

| Part | Needed | Suggested buy | First experiment | Example supplier |
|----|----|----|----|----|
| 10 µF electrolytic, rated at least 16 V | 3 | 5 | 1 | [667-ECA-1EM100B (25 V)](https://www.mouser.com/en/ProductDetail/Panasonic-Industry/ECA-1EM100B?qs=rMMd5vBiahrNyc2p3snNiw%3D%3D) |
| 10 nF (0.01 µF) ceramic, rated at least 16 V | 1 | 5 | 1 | Through-hole ceramic capacitor |
| 1 µF ceramic, rated at least 16 V | 1 | 5 | 9 | [80-C322C105K5R5TA](https://www.mouser.com/en/ProductDetail/KEMET/C322C105K5R5TA?qs=AbvNRnczFITGWoFhoGOLBw%3D%3D) |

Each breadboard timer that you keep needs its own 10 µF timing capacitor. The 10 nF ceramic filters the NE555 control pin in Experiment 1. The 1 µF ceramic steadies the supply rail in Experiment 9. The remaining ceramics are spares.

### Breadboards and wiring

These are the same supplies listed in [The Bench](https://fullstackelectronics.com/the-bench.html.md), so count what you already have.

| Item | Quantity | Example supplier |
|----|----|----|
| Full-size breadboard (I use the BusBoard BB830) | 3 | [854-BB830](https://www.mouser.com/en/ProductDetail/BusBoard-Prototype-Systems/BB830?qs=VEfmQw3KOauhPeTwYxNCaA%3D%3D) |
| 22 AWG solid-core hook-up wire | One set of reels in several colours | [485-1311](https://www.mouser.com/en/ProductDetail/Adafruit/1311?qs=GURawfaeGuBbUKgxUfZ%252BxQ%3D%3D) (six 25 ft spools) |
| Jumper leads, pin to pin and pin to socket | One pack of each, with at least eight pin-to-socket leads for Experiment 21 | [854-ZW-MM-10](https://www.mouser.com/en/ProductDetail/BusBoard-Prototype-Systems/ZW-MM-10?qs=I13xAFqYpRS2vPPNkDxO%2FA%3D%3D), [854-ZW-MF-10](https://www.mouser.com/en/ProductDetail/BusBoard-Prototype-Systems/ZW-MF-10?qs=kfEmHhwILN%2FEIQHUjLuVTQ%3D%3D) |

## PCB components · Stage Four

The table below covers one PCB and matches the assembly list in [Experiment 20](https://fullstackelectronics.com/experiments/20-assembly-day.html.md). Buy spares for assembly. The suggested quantities allow for dropped or damaged parts. Order more if you plan to populate several boards.

The resistors and the ceramic capacitor use the 0805 size code: each part measures 0.08 by 0.05 inches, about 2.0 by 1.25 mm. The transistors use the SOT-23 package. Check both the value or model and the package when you order.

| Part and package | On one PCB | Suggested buy | Example supplier |
|----|----|----|----|
| MMBT3904 (NPN, SOT-23) | 16 | 25 | [863-MMBT3904LT1G](https://www.mouser.com/en/ProductDetail/onsemi/MMBT3904LT1G?qs=HVbQlW5zcXUYZ2Fy0YF3FQ%3D%3D) |
| MMBT3906 (PNP, SOT-23) | 7 | 15 | [863-MMBT3906LT1G](https://www.mouser.com/en/ProductDetail/onsemi/MMBT3906LT1G?qs=HVbQlW5zcXXO9RcjXx8aQw%3D%3D) |
| 4.7 kΩ 0805 | 8 | 20 | [603-RC0805FR-074K7L](https://www.mouser.com/en/ProductDetail/YAGEO/RC0805FR-074K7L?qs=VLOqbHBAO5cYXbrd7RTmuQ%3D%3D) |
| 10 kΩ 0805 | 10 | 20 | [603-RC0805FR-0710KL](https://www.mouser.com/en/ProductDetail/YAGEO/RC0805FR-0710KL?qs=7bY8808IzHq6vrU3BeiiYw%3D%3D) |
| 1 kΩ 0805 | 2 | 10 | [603-RC0805FR-071KL](https://www.mouser.com/en/ProductDetail/YAGEO/RC0805FR-071KL?qs=1ogmaHw32WJjeGY0DHXakQ%3D%3D) |
| 100 kΩ 0805 | 1 | 5 | [603-RC0805FR-07100KL](https://www.mouser.com/en/ProductDetail/YAGEO/RC0805FR-07100KL?qs=8Y8p%252BasKcI7rEWn6FcVdAA%3D%3D) |
| 0.1 µF 0805 | 1 | 5 | [80-C0805C104K5RAC](https://www.mouser.com/en/ProductDetail/KEMET/C0805C104K5RAC?qs=r%2FVmNO8Tjq4%2F8ymSnGP6Jw%3D%3D) |

For the listed onsemi parts, the device codes are `1AM` for the [MMBT3904](https://www.onsemi.com/pdf/datasheet/mmbt3904lt1-d.pdf) and `2A` for the [MMBT3906](https://www.onsemi.com/download/data-sheet/pdf/mmbt3906lt1-d.pdf). Other manufacturers can use other codes. Keep parts in their labelled packaging. Check the manufacturer's marking diagram and pinout before assembly.

### Using a component sample book

I found this surface-mount (SMD) component sample book on eBay. It groups the parts by type and value in labelled plastic pockets. You can use a sample book like this, or buy the parts individually from the table above. Check the contents, packages and quantities before you buy. Some assortments contain only resistors or capacitors.

![Front cover of an SMD component sample book found on eBay, listing 5435 surface-mount parts organised by type and value](https://fullstackelectronics.com/assets/img/smd-assortment-0805-label.jpg)

The SMD component sample book I found on eBay. Its cover lists the parts inside.

### Header and PCB

| Item | Quantity | Notes |
|----|----|----|
| Vertical 1×8 pin header, 2.54 mm pitch | 1 per board | J1, the module's eight pins. You can cut a longer strip to length. Example: [200-TSW10807GS](https://www.mouser.com/en/ProductDetail/Samtec/TSW-108-07-G-S?qs=iT52DjcXuds4z2KTidkgfQ%3D%3D) |
| Fabricated PCB | 1 to assemble, plus optional spares | Order after the checks in [Experiment 19](https://fullstackelectronics.com/experiments/19-the-pre-fab-ritual.html.md). Minimum order quantities, board prices and delivery charges depend on the manufacturer. |

The timing resistors, the 10 µF capacitor, the LED and its 220 Ω resistor stay outside the module. In Experiment 21 you reuse Experiment 1's breadboard circuit and replace the NE555 with your PCB. You don't need another set of timing parts for that step.

[The Bench](https://fullstackelectronics.com/the-bench.html.md) lists the solder wire, no-clean flux gel, wick, isopropyl alcohol, swabs and tweezers. Include them in your assembly preparations if you haven't already.

## Shopping checklist

These are the suggested purchase quantities from the tables, including spares. Tick an item when you have enough. This browser saves your ticks.

### Breadboard components

50 × 2N3904 (NPN, TO-92)

20 × 2N3906 (PNP, TO-92)

2 × NE555 (8-pin DIP)

2 × LM393 (dual comparator, 8-pin DIP)

2 × CD4001B (quad NOR gate, 14-pin DIP)

10 × Red LED, 5 mm

50 × 10 kΩ, ¼ W through-hole

10 × 1 kΩ, ¼ W through-hole

20 × 4.7 kΩ, ¼ W through-hole

5 × 2.2 kΩ, ¼ W through-hole

5 × 100 kΩ, ¼ W through-hole

10 × 220 Ω, ¼ W through-hole

5 × 10 µF electrolytic capacitors, rated at least 16 V

5 × 10 nF (0.01 µF) through-hole ceramic capacitors, rated at least 16 V

5 × 1 µF through-hole ceramic capacitors, rated at least 16 V

### Breadboards and wiring, shared with The Bench

3 full-size breadboards

22 AWG solid-core hook-up wire in several colours

Pin-to-pin and pin-to-socket jumper leads, including eight socket leads for the PCB

### PCB components

25 × MMBT3904 (NPN, SOT-23)

15 × MMBT3906 (PNP, SOT-23)

20 × 4.7 kΩ 0805

20 × 10 kΩ 0805

10 × 1 kΩ 0805

5 × 100 kΩ 0805

5 × 0.1 µF 0805

1 × vertical 1×8 header, 2.54 mm pitch, per board

PCB ordered after Experiment 19’s design checks

[Start Experiment 1 →](https://fullstackelectronics.com/experiments/01-the-reference-555.html.md)
