Step-by-step example: exploring the ESP32-PoE schematic

Practise following a power net, finding every label with the same name, tracing a signal, searching parts and exporting CSV on the open-hardware Olimex ESP32-PoE schematic.

Last updated: 2026-10-09

This walkthrough is meant to be followed with the example schematic open. It is the ESP32-PoE board (revision I), published by Olimex of Bulgaria under the Apache 2.0 licence: an ESP32 board powered and networked over one Ethernet cable (PoE). Power supply, Ethernet, USB-to-serial, buttons and expansion connectors all fit on one sheet, which makes it good practice. The original file is in the Olimex GitHub repository.

Step 1: open the example

1. Choose Try an example on the home page, or Try an example schematic in the tool. The file is fetched from this site and analyzed in your browser.
2. A few seconds later the whole sheet fits the screen and the list shows Nets 40 and Parts 129.
3. Block titles such as Power Supply, ESP32-WROOM-32 Module, Ethernet, USB to UART and Buttons are visible. Zoom with the wheel or two fingers to look around.

Step 2: follow a power net

1. In the Nets tab, under Power, pick +3.3V. The ×11 next to it means there are eleven labels with that name.
2. Every wire on +3.3V turns cyan and the rest fades. From the regulator output to the ESP32 module, button pull-ups, SD card and expansion connector, you see everywhere this supply is used.
3. Click +3.3V in the list again, or use Labels ▶ in the selection panel, to visit the labels one by one (1/11, 2/11 …). No power symbol scattered across the sheet is missed.
4. For contrast, pick +3.3VLAN. Similar name, but it is a separate supply for the Ethernet chip, so a different area lights up — good practice for not mixing up look-alike rails.

Step 3: trace one signal

1. Type ESP_EN in the search box. After a short pause the view jumps to the first match, and the list shows ESP_EN ×4.
2. Pick ESP_EN in the list: the enable (reset) signal is highlighted from the module's EN pin to the reset button and the auto-reset circuit on the USB-to-serial side.
3. Step through the four labels and note which parts (pull-up resistor, capacitor, button) sit on the signal at each place.
4. Clicking any highlighted wire selects the same net. Click empty space or press Esc to clear it.

Step 4: find a part

1. Type R1. Search matches parts of words, so R10–R19 are found too, but R1 itself comes first and the bar shows "exact 1".
2. Switch to the Parts tab: R1 is the first row. Click it to jump there.
3. Parts with a value written next to them show it in the list (for example 22uF/6.3V/20%/X5R/C0603 on a capacitor). If a value is empty, check the drawing; Finding parts explains why it happens.

Step 5: save the lists

1. Clear the search, then choose Parts CSV in the Parts tab to save references, values and pages for all 129 parts.
2. Nets CSV in the Nets tab saves the 40 nets with their type and label count — handy for sorting in a spreadsheet or checking against a BOM.

Wrap-up

These five steps answer most everyday questions on any schematic: where a supply is used, where a signal goes, and where a part is. Now try the same with your own schematic PDF. If symbols and labels still feel unfamiliar, read Reading schematics and datasheets first.