DIY bulb tester - design, schematic, enclosure, plans to expand with an ammeter
TL;DR
- Built a DIY bulb tester for safely repairing an old radio, with a custom 3D-printed enclosure and panel layout.
- A KCD4 main switch selects TESTER or BYPASS mode, while three KCD3 switches enable different bulb wattages to control limiting current.
- The enclosure was printed on an Ender 3 V3 Plus, uses 4 mm walls, M3 screws with brass inserts, and an IEC inlet with double 6A fuses.
- Wiring uses WAGO 221 connectors, LgY 1.5 mm² wire, and an AD16 voltmeter behind the input socket; the next upgrade is an output ammeter.
Good morning.
My first project. Some time ago I wanted to repair an old radio from my father-in-law as a gift for my wife, but I didn't want to burn it down extra. So I came up with a bulb tester. It was supposed to be as simple as possible, but somehow I got worked up and added a few extra components. I plan to add one more - an ammeter on the output. The whole layout, as well as the design with the case printing, realised by me.
Key information about the design:
1. Enclosure: Designed in CAD and printed on an Ender 3 V3 Plus. The walls are 4 mm thick, which provides great rigidity.
2. Assembly: All components (sockets, panel) are mounted with M3 screws screwed into brass inserts molded into the plastic. This avoids the threads becoming worn in the print.
3. Power supply: I used an IEC socket with a double 6A fuse. The filter limits the continuous current to 6A (about 1380W), which is sufficient in my conditions.
4. Operating logic: The main switch KCD4 allows you to select TESTER mode (via the bulbs) or BYPASS mode (direct). The three switches KCD3 allow the selective connection of bulbs of different wattages, giving control over the limiting current.
5. Safety: the PE protective conductor is pulled directly from the power socket to the pin in the Schuko output socket.
6. Interior: Connections based on WAGO 221 connectors (star topology) and LgY 1.5 mm^2 wires.
7. Monitoring: AD16 voltmeter plugged in directly behind the input socket (piggyback), so it works independently of the tester mode. (As an indicator that the IEC socket is switched on.
8. Plans to add an Ammeter on the output to monitor the current drawn.
My first project. Some time ago I wanted to repair an old radio from my father-in-law as a gift for my wife, but I didn't want to burn it down extra. So I came up with a bulb tester. It was supposed to be as simple as possible, but somehow I got worked up and added a few extra components. I plan to add one more - an ammeter on the output. The whole layout, as well as the design with the case printing, realised by me.
Key information about the design:
1. Enclosure: Designed in CAD and printed on an Ender 3 V3 Plus. The walls are 4 mm thick, which provides great rigidity.
2. Assembly: All components (sockets, panel) are mounted with M3 screws screwed into brass inserts molded into the plastic. This avoids the threads becoming worn in the print.
3. Power supply: I used an IEC socket with a double 6A fuse. The filter limits the continuous current to 6A (about 1380W), which is sufficient in my conditions.
4. Operating logic: The main switch KCD4 allows you to select TESTER mode (via the bulbs) or BYPASS mode (direct). The three switches KCD3 allow the selective connection of bulbs of different wattages, giving control over the limiting current.
5. Safety: the PE protective conductor is pulled directly from the power socket to the pin in the Schuko output socket.
6. Interior: Connections based on WAGO 221 connectors (star topology) and LgY 1.5 mm^2 wires.
7. Monitoring: AD16 voltmeter plugged in directly behind the input socket (piggyback), so it works independently of the tester mode. (As an indicator that the IEC socket is switched on.
8. Plans to add an Ammeter on the output to monitor the current drawn.
Comments
This is interesting and helpful I often use such a tester but on one bulb. If I can advise, the bypass/test switch should be such that it always goes back to test because sometimes when checking the... [Read more]
Hello, i was a little confused by the title at the beginning, as in the old days, when there was a shortage of everything, especially meters, testers where the indicating element was an incandescent bulb... [Read more]
Very cool you came up with this tester. I hope it will perform well. [Read more]
A cool and useful item. I use one too, but in my house it's more coarse. If you don't have one then I would recommend some sort of indicator that you have voltage applied to the output socket - while still... [Read more]
Thank you. I need to look for such a switch. This is my first project so I haven't taken everything into consideration yet :) Added after 1 [minute]: Thank you! This is my first project, I'll... [Read more]
In my opinion, all types of projects, even very simple ones, should be accompanied by a wiring diagram. Then you don't have to read the description many times to understand what it's all about. A quick... [Read more]
I completely agree with this. As soon as I started reading the post, I looked for a diagram but there wasn't one. Anyway, great idea for inspiration. I've been planning to build something like this for... [Read more]
Nicely done. Although the vago connectors could have been avoided Don't you think it would be more useful to measure the voltage on the output socket ? [Read more]
For a first project, the design is very impressive, it also looks quite safe and also reusable without fear of damage. And then there's the noble motivation - repairing a commemorative radio. How did... [Read more]
You can still make an extra socket for a kettle of water, this increases the short-circuit current to about 10A, useful for power tools. But in your case, the filter may not be able to cope with it. I... [Read more]