electronics

An Interesting Two-Transistor Relay Timer

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I came across the printed circuit board for this circuit completely by accident. It looked like an interesting and clever little design, and I had more than enough suitable parts lying around in my component drawers, including a pile of spare relays. So I decided to build one and measure what it could actually do. … Read more

On the Teardown Bench: Radtel RT-470 – What’s Inside a Modern Handheld Radio?

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This time, the device on the teardown bench is not broken. My Radtel RT-470 is fully functional and gets regular use; it simply needed a thorough cleaning. For that reason, I did not take it apart any further than what you can see in the photographs. Even so, there is plenty to discover about how … Read more

Repairing an electronic fluorescent starter

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The other day, I explained to my partner how a fluorescent starter works and what the ballast is for. I won’t go into it now—if you’re interested, look it up. I also explained why electronic ballasts are supposedly better than traditional ones. Well, I was wrong: they aren’t better. Every self-respecting electrician or hardware supplier … Read more

Strong LED flashing light

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This circuit is a simple flasher that produces strong and short flashes. If you already know how a transistor works, you’ll have no trouble understanding how this thing operates. You can find the circuit on Tinkercad here: 👉 https://www.tinkercad.com/things/jn4ZX0OA4qi-flashing-light Although it works in a very simple way, this circuit actually exceeds the capabilities of Tinkercad’s … Read more

Simple Siren

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A popular variant of the well-known NE555 timer IC is the NE556, which contains two timers. With this IC, you can build a simple siren. This siren alternates between two tones, similar to old police car sirens, while also flashing a blue and a red LED. You can test the circuit in Tinkercad: 👉 https://www.tinkercad.com/things/lsxjw2LzvA7-police-siren … Read more

How to Clean a Soldering Iron Tip

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Back in our Pioneer days, many of us soldered with a Czechoslovak “instant soldering iron,” for which we bent the tip ourselves from stripped copper electrical wire. Today, a single tip for a modern soldering station costs around €3–5 HUF, so it’s not wise to waste them carelessly! There are plenty of guides online about … Read more