Make a Voltage Divider in typeCAD

In this example, we will make a voltage divider.

This is the equivalent circuit:

Very simple, just two resistors. Voltage on the top, ground on the bottom, with half the voltage in the middle.

Make a typeCAD project

From a terminal, run:

npx @typecad/create-typecad
🤖 typeCAD Project Creator
✔ Create a project: Project
✔ Project name? voltage_divider
✔ Create a PlatformIO project for firmware? No
✔ Initialize a git repo? No
? Optional packages
+ Project folders created
+ KiCAD project created
+ Creating npm package
+ Installing dependencies
+ Finished
+ Open voltage_divider.code-workspace in VS Code to get started

Call this project voltage_divider. No need to make a PlatformIO project or initialize a git repo unless you want to. No extra packages are needed either, but feel free to add them later if you want.

Like the output said, open voltage_divider.code-workspace in VSCode to get started. You should see NPM Scripts in the sidebar with a few scripts. If you don’t, click View > Open View > and enter NPM Scripts.

Test build

Click the 🤖 Build script and you should see some build output in a terminal. If everything is installed correctly, you should see this:

🏁 typeCAD starting...
R1 created
R1 added
./build/voltage_divider.net file written
🏁 typeCAD finished

The R1 resistor is there as test code. It’s contained in ./src/voltage-divider/index.ts.

Making resistors

You can delete most of the starter code so you’re left with this:

import { Schematic } from "@typecad/typecad"
import { Resistor } from '@typecad/passives/0603';

let typecad = new Schematic('voltage_divider');
let r1 = new Resistor({ value: '1kohm' });

typecad.create(r1);

This code creates a Schematic object called typecad and a Resistor object called r1. We need two resistors, so let’s make another.

import { Schematic } from "@typecad/typecad"
import { Resistor } from '@typecad/passives/0603';

let typecad = new Schematic('voltage_divider');
let r1 = new Resistor({ value: '1kohm' });
let r2 = new Resistor({ value: '1kohm' });

typecad.create(r1, r2);

Don’t forget to add r2 to the create method.

Resistor properties

Components have several properties, the one we’re concerned with here is value (VSCode tooltips will tell you all the other properties). Our example schematic used 10kOhm resistors, so let’s change that.

import { Schematic } from "@typecad/typecad"
import { Resistor } from '@typecad/passives/0603';

let typecad = new Schematic('voltage_divider');
let r1 = new Resistor({ value: '10kohm' });
let r2 = new Resistor({ value: '10kohm' });

typecad.create(r1, r2);

Build

Build the schematic again. Click the ✳️ Open Board script. When KiCAD opens, click the Net icon and locate the voltage_divider.net file. Then click Update PCB.

You should see two resistors on the board.

Connections

For passive components, it is typical to just use a r1.pin(x) method to get a Pin object. Resistors have two pins and no polarity, so we can use either pin.

To create our voltage divider, we need to connect our two resistors together.

import { Schematic } from "@typecad/typecad"
import { Resistor } from '@typecad/passives/0603';

let typecad = new Schematic('voltage_divider');
let r1 = new Resistor({ value: '10kohm' });
let r2 = new Resistor({ value: '10kohm' });

typecad.net(r1.pin(2), r2.pin(1));

typecad.create(r1, r2);

If we want, we can give this connection a name so it is clearer in KiCAD.

typecad.net(r1.pin(2), r2.pin(1));
typecad.named('VDIV').net(r1.pin(2), r2.pin(1));

Build again

When you build and import the netlist again, you’ll see the connection we just made.

Extras

We need power to make this circuit do something, but that will be covered in a later example.