Hi,
I just built this: https://audiokarma.org/forums/index.php?threads/dim-bulb-tester-build-and-how-to.808399/
And I think everything is fine. However, is there any real-world test (to ensure the wiring is 100% correct) I can do to pre-test it before using it to test my amp? Like plugging it into some cheap/durable electronic device and turning it on? Yes, this is a little paranoid, but more about better visualizing how it works and confirming for my education.
I did deliberately use the 'old' style switch and used the decora style outlet for...style 😀
Picture for fun, obviously this does not show the wiring!
I just built this: https://audiokarma.org/forums/index.php?threads/dim-bulb-tester-build-and-how-to.808399/
And I think everything is fine. However, is there any real-world test (to ensure the wiring is 100% correct) I can do to pre-test it before using it to test my amp? Like plugging it into some cheap/durable electronic device and turning it on? Yes, this is a little paranoid, but more about better visualizing how it works and confirming for my education.
I did deliberately use the 'old' style switch and used the decora style outlet for...style 😀
Picture for fun, obviously this does not show the wiring!
Unplug the tester. Connect a short circuit across the test outlet. Insulate the connection from touch.
Plug in the tester. If the tester works, the bulb will light up normally when switched on.
Of course, the bulb should not light up at all with nothing plugged into the test outlet and switched on.
Plug in the tester. If the tester works, the bulb will light up normally when switched on.
Of course, the bulb should not light up at all with nothing plugged into the test outlet and switched on.
Thanks! Funny enough you just typing that made the lightbulb go off (figuratively and pun intended), and I just tested it (it literally worked!). It now makes sense and I understand that L-N loop on the test plug is where everything is happening.
As a follow-up, I understand when I actually test the amp, it should be bright then quickly dim. If it stays illuminated...BAD...shut off immediately and check for faults. Why does the bulb NOT remain illuminated? I know there is the large, initial inrush of current to charge the caps...and with no load (the amp itself) attached there is very little current draw (just whatever is needed to keep the caps topped up, which is almost nothing). Obviously there is still current flowing through the filament of the bulb otherwise it would not work.
https://diyalephj.blogspot.com/2020/11/building-assembling-and-testing-power.html
As a follow-up, I understand when I actually test the amp, it should be bright then quickly dim. If it stays illuminated...BAD...shut off immediately and check for faults. Why does the bulb NOT remain illuminated? I know there is the large, initial inrush of current to charge the caps...and with no load (the amp itself) attached there is very little current draw (just whatever is needed to keep the caps topped up, which is almost nothing). Obviously there is still current flowing through the filament of the bulb otherwise it would not work.
https://diyalephj.blogspot.com/2020/11/building-assembling-and-testing-power.html
If the bulb's wattage is too low, it will light brightly even if your device has no problems.
Your device should operate normally without fully lighting a bulb that is roughly 1.5 to 2 times the device's stated wattage.
Ahh, got it. I am assuming with no amp boards connected (just the power supply with no load), the power draw is probably just a dozen or so watts, if that.
@canonken , said another way, a high wattage bulb will light when "high" current passes through it. Since the bulb and the device under test are connected serially, the device under test should limit the current passing through the bulb.
The jig works by assuming that your device under test (in steady state) draws much less current than the bulb needs; this is why you want a "high wattage" bulb.
When initially powered on, the device under test draws high current (to fill capacitors, usually) which lights the bulb, and then "settles down" to draw a lower level of current, and so the bulb dims. The current is still flowing through the light bulb, but the level is too low to make it shine.
Kind regards,
Drew
The jig works by assuming that your device under test (in steady state) draws much less current than the bulb needs; this is why you want a "high wattage" bulb.
When initially powered on, the device under test draws high current (to fill capacitors, usually) which lights the bulb, and then "settles down" to draw a lower level of current, and so the bulb dims. The current is still flowing through the light bulb, but the level is too low to make it shine.
Kind regards,
Drew
I would NOT test , precisely, with a full short 😱
It´s a just built device which may have a wiring error (such a bypassed bulb socket) so "test" would yield sparks , fire, or at least breaker tripping.
Sounds like jumping from a plane to "test" an unknown/suspect parachute 😱
I suggest instead plugging in a significative load, such as a lamp desk with a bulb same rating as the one in the tester.
If it works, both will shine orange; if there is an error, maybe second bulb shines bright, or none of them at all.
Play it safe.
I too fear a dead-short in the hands (and house) of a novice. I'd get the waffle-iron or other big safe load. A 1,000W iron or heater on a 60W incandescent lamp will give 99% brightness and not enough heat to warm a flea.
Yes, two equal lamps is another good test, but not as severe.
Yes, two equal lamps is another good test, but not as severe.
Yes, JMF (and PRR), that is the procedure I adopted when testing my dim bulb tester.
Or fuses in my case... The last time I plugged in something that was a short, the lights just went out - I didn't even get a spark when I plugged it in.
And in reality, it is a VERY simple series circuit. I wouldn't worry too much.
Keep in mind like the OP, I'm in a 120V 15A branch circuit country. I would be more reluctant to short a UK plug...
And in reality, it is a VERY simple series circuit. I wouldn't worry too much.
Keep in mind like the OP, I'm in a 120V 15A branch circuit country. I would be more reluctant to short a UK plug...
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Plug the toaster to it. Sorry if it was suggested, i only read the first post.
Thanks Pano.
Next time I will lick exposed mains wires to check for presence/absence of voltage, what are GFCI for anyway? 😱
Don't be a drama queen. Plugging in a simple circuit which might have a short and trip a breaker is hardly comparable to licking the GD power line to test a GFI!
What? That's the way I always test them. I enjoy the taste. (sometimes I hit reset 2 or 3 times)
Then WHY build a DBT at all?
Just plug the d*mn amp into the wall to save time and money.
Hey, why waste time with fuses and fuse holders at all?