How to Identify a Capacitor's Outside Foil Lead Without an Oscilloscope

In this beginner-friendly tutorial, I'll show you how to identify a modern film capacitor's outside foil lead without using an oscilloscope. Most modern film capacitors no longer indicate which lead is connected to the outside foil, making it difficult for hobbyists restoring vintage radios, tube amplifiers, and other vintage electronics. Update: "After doing some more research, I learned that ceramic disk capacitors are constructed differently from rolled film or paper capacitors and don't have a true inside or outside foil. The blue ceramic disk capacitor served as a good comparison because there was essentially no meaningful difference in the test, unlike the film capacitor where the outside foil orientation was much more noticeable. I'll be sure to mention that in a future video." Since I don't own an oscilloscope or a guitar amplifier, I developed a simple method using inexpensive tools that almost anyone can afford: • Small mono amplifier • Small Speaker • Smartphone sound level (SPL) app I'll walk you through the entire process step by step so you can easily identify the outside foil lead yourself. This method is especially useful for: • Vintage radio restoration • Tube amplifier restoration • Restuffing paper capacitors • Restoring antique electronics • Beginner electronics hobbyists If you enjoy vintage radio restoration and electronics tutorials, consider subscribing for more beginner-friendly restoration videos. 👍 If this video helps you, please Like, Subscribe, and Share! As an Amazon Associate, I earn from qualifying purchases — at no extra cost to you. These links help support the channel. Thank you! Equipment Used • Small Mono Amplifier 3.5MM: https://amzn.to/4fQOwen • OontZ Small Bluetooth Speaker: https://amzn.to/4gQFOyQ • Modern Film Capacitors: https://amzn.to/4yxg0Oz • Alligator clips electrical mini: https://amzn.to/4b50wHq • 3.5mm Replacement Plug Jack: https://amzn.to/4vEcSgX • NIOSH Sound Level Meter app: https://apps.apple.com/us/app/niosh-s...