This is the second part of a two-video build series in which Electronic-On assembles the classic XR2206-based function generator kit sold cheaply on AliExpress. The XR2206 is a monolithic function generator IC that can produce sine, square, and triangle waves over a wide frequency range — a venerable chip that's still a great teaching vehicle for understanding waveform synthesis, RC timing networks, and amplitude/symmetry trimming.

What makes this installment particularly useful is the focus the title flags: capacitor polarity. Cheap DIY kits frequently ship with electrolytic capacitors whose silkscreen orientation is ambiguous, mislabeled, or simply easy to misread, and reversed electrolytics are one of the most common failure modes for first-time kit builders — they can leak, bulge, or explode, and at minimum they prevent the circuit from working correctly. Watching someone walk through the polarity check on a real board, point out which caps are the gotchas, and explain why it matters is exactly the kind of hands-on guidance you don't get from the kit's photocopied instructions.

If you've ever been tempted by the $5–10 XR2206 kits but were unsure whether they're worth the time, pairing this with the earlier "Empezamos a montar" video gives you a complete walkthrough from unboxing to working instrument, in Spanish, with practical troubleshooting commentary.