The wire link might be in place of a thermal fuse which is sometimes attached to the transistor heatsink. The tiny toroid usually has two multiturn windings providing the base drive to the big transistors, and a single loop in series with the main output transformer. The circuit is "plucked" on each half wave by a simple capacitor, resistor and diac arrangement to start it oscillating.
I've used these HF supplies to drive the little HV transformers in inverters for running short neon tubes. I put a small cap in series with the winding to limit the current. In the past the neon sign industry experimented with using a single high frequency converter to drive loads of little transformers in large signs.
great stuff!, I figured those lighting power supplies were proper SMPSU's, but it seems they are much more simplified. I had no idea you could drive a flyback with the output either!. definitely not high powered but still a great novice HV project! your right about the burn too. I remember the smell of charred flesh more than the slight tingle I got from a similar size driver. CCFL psu's from flat bed scanners have the same effect on fingers too :D
Thank you for another great video! I barely understand what you talk about since I'm not into electronics but I still really enjoy watching your videos!
It's a Safebloc (not sure that company is still around but it's become a generic name, like Hoover). Allows easy & relatively safe connection of random wires to the mains.
Interesting, I'd have expected a lot more in there, (a) because it's dimmable and (b) because it's an electronic transformer with an AC output. Thanks for tearing and sharing :)
Are the transformers/fat inductor any good for making high-voltage step up converters? I have a few of these lying around in the garage that I'm thinking about scavenging parts from.
There is a SMD NTC thermistor on there , presumably for thermal protection, althouhgh it may be that some countries' safety standards require a supply cutout.
AC is actually better for halogen lamps than DC as the halogen gasses can asymmetrically corrode the filament on DC. Also, one problem with most of these is that they will fry if unloaded.
Thank you for your illuminating videos. Looks jus like the set up on my bench at the mo ... I'm trying to figure out a plugin retrofit converter for 12V LED lamps but not having much luck. Any pointers on a simple and efficient design would be appreciated.
I have a dimmer lamp, but unfortunately isn't working iam not really clued up with transformer and I haven't really got anything to test if this as a fault on it,I did buy 12 volt bulbs but iam not sure of the watts,I really love this stand up floor lamp has it as crystal droplets coming from it . I have even changed the fuse but still not working :-( can some guild me or advise me what to do, I'd really appreciate it thanks
I notice the high frequency is modulated with 50Hz, so it probably would still be very painful if you came into contact with the output of the flyback.
MrOpenGL I don't see how there is any difference between 12v halogens and 230v halogens. It's the same filament and the same filler gas. Besides, the G4 fitting is inferior to gu10.
***** I agree on the GU10 fitting being superior than G4 (G4 if moved can drop the lamp!!), the problem is that filaments last less if they are thinner. Because 230V is higher voltage than 12V, the filament needs to be much longer and thinner than the one for 12V in order to have the same power passing through it (the power in a lightbulb is governed by Ohm's law). Since a 230V filament is VERY VERY thin and tightly coiled together, it cannot be run very hot (2900°C) as a 12V filament can, so it is underrated and run only at about 2200°C producing a white light that's less bright than the 12V one and more yellowish, looking almost like old incandescend lightbulbs (a bit better but not that much). The same problem is present where 24V G4 halogens are a little less bright and last half of the life than the 12V ones. In my house I have both GU10 halogens and G4 halogens. G4s are on at the same time than the GU10s. The GU10s are MUCH less bright and more powerful (35W) than the 20W G4s, and they burn out once every 5-6 months while G4s last for 8+ years (much of the fixtures still have the original ones!). All the 12V fixtures have normal 50Hz transformers instead of electronic ones.
MrOpenGL I still prefer lamps with 230v halogens because you can retrofit leds into them without issue, whereas retrofitting led into g4 means you have to replace the transformer (or live with a constantly flickering bulb). This completely negates your argument, because with a retrofit you can put any colour temp you want in there.
***** My argument only concerned standard non-LED bulbs, and you don't have to replace the transformer just to add arectifier and a capacitor! Not to mention that I still prefer the light temp and output of the G4 than the one of the LED bulbs.
Also notable for causing electrocutions when used casually and wires are misinserted. Very useful in a workshop though.
The wire link might be in place of a thermal fuse which is sometimes attached to the transistor heatsink. The tiny toroid usually has two multiturn windings providing the base drive to the big transistors, and a single loop in series with the main output transformer. The circuit is "plucked" on each half wave by a simple capacitor, resistor and diac arrangement to start it oscillating.
I've used these HF supplies to drive the little HV transformers in inverters for running short neon tubes. I put a small cap in series with the winding to limit the current. In the past the neon sign industry experimented with using a single high frequency converter to drive loads of little transformers in large signs.
great stuff!, I figured those lighting power supplies were proper SMPSU's, but it seems they are much more simplified.
I had no idea you could drive a flyback with the output either!. definitely not high powered but still a great novice HV project!
your right about the burn too. I remember the smell of charred flesh more than the slight tingle I got from a similar size driver. CCFL psu's from flat bed scanners have the same effect on fingers too :D
Thank you for another great video! I barely understand what you talk about since I'm not into electronics but I still really enjoy watching your videos!
It's a Safebloc (not sure that company is still around but it's become a generic name, like Hoover). Allows easy & relatively safe connection of random wires to the mains.
Interesting, I'd have expected a lot more in there, (a) because it's dimmable and (b) because it's an electronic transformer with an AC output. Thanks for tearing and sharing :)
Fairly well made little unit!
Great explanation and LOPT experiment at the end. Thanks for posting.
quite a nice spark .usually they run on 16 khz.good teardown.
sudden ending, we meet again!
great vid!!!
Good vid! Cheers for the upload Mike
Would be great if you could do a video like this for the DC 12v versions of these power supplies for lEDs.
Hi
Is the little transformer in the PCB an ordinary 50/60 Hz or it workes on higher frequency?
Waiting for your highly informative answer.
Are the transformers/fat inductor any good for making high-voltage step up converters? I have a few of these lying around in the garage that I'm thinking about scavenging parts from.
There is a SMD NTC thermistor on there , presumably for thermal protection, althouhgh it may be that some countries' safety standards require a supply cutout.
That must kick out lots of harmonics.
thanks for passing on your knowledge
AC is actually better for halogen lamps than DC as the halogen gasses can asymmetrically corrode the filament on DC.
Also, one problem with most of these is that they will fry if unloaded.
Thank you for your illuminating videos.
Looks jus like the set up on my bench at the mo ... I'm trying to figure out a plugin retrofit converter for 12V LED lamps but not having much luck. Any pointers on a simple and efficient design would be appreciated.
Get a thing like the one in the video. Put rectifier and capacicator across the output. Enjoy either a working 12v power supply or a cool explosion.
5:10 *scratch scratch*
This looks like it might be a resonant inverter topology similar to what is found in a CFL.
Can this transformer be used to step up voltage? I need transformer for 7amp inverter.
I have a dimmer lamp, but unfortunately isn't working iam not really clued up with transformer and I haven't really got anything to test if this as a fault on it,I did buy 12 volt bulbs but iam not sure of the watts,I really love this stand up floor lamp has it as crystal droplets coming from it . I have even changed the fuse but still not working :-( can some guild me or advise me what to do, I'd really appreciate it thanks
this stuff is pretty durable, it would take a bit of effort to damage it.
I notice the high frequency is modulated with 50Hz, so it probably would still be very painful if you came into contact with the output of the flyback.
@Reiuyi hmm, maybe because 12v in pools isnt as dangerous?
I will take a transformer over the inverters any day. I have one of the inverter ones and it gets hotter than the lights it's powering!
Thanks to Ed Systems (Aussie 50) for the direction to this channel
They're both high-frequency.
Meh I hate those things, they inject LOTS of noise into the mains, and the one for my workbench lamp sometimes interferes with projects! :(
Well I guess it was at the end ;)
Pretty much worthless nowadays due to 230v halogens becoming the norm, though interesting look at this circuit regardless
230V halogen are rubbish, they don't last as long due to the thin filament and produce less light.
MrOpenGL I don't see how there is any difference between 12v halogens and 230v halogens. It's the same filament and the same filler gas. Besides, the G4 fitting is inferior to gu10.
*****
I agree on the GU10 fitting being superior than G4 (G4 if moved can drop the lamp!!), the problem is that filaments last less if they are thinner. Because 230V is higher voltage than 12V, the filament needs to be much longer and thinner than the one for 12V in order to have the same power passing through it (the power in a lightbulb is governed by Ohm's law). Since a 230V filament is VERY VERY thin and tightly coiled together, it cannot be run very hot (2900°C) as a 12V filament can, so it is underrated and run only at about 2200°C producing a white light that's less bright than the 12V one and more yellowish, looking almost like old incandescend lightbulbs (a bit better but not that much). The same problem is present where 24V G4 halogens are a little less bright and last half of the life than the 12V ones.
In my house I have both GU10 halogens and G4 halogens. G4s are on at the same time than the GU10s. The GU10s are MUCH less bright and more powerful (35W) than the 20W G4s, and they burn out once every 5-6 months while G4s last for 8+ years (much of the fixtures still have the original ones!). All the 12V fixtures have normal 50Hz transformers instead of electronic ones.
MrOpenGL I still prefer lamps with 230v halogens because you can retrofit leds into them without issue, whereas retrofitting led into g4 means you have to replace the transformer (or live with a constantly flickering bulb). This completely negates your argument, because with a retrofit you can put any colour temp you want in there.
*****
My argument only concerned standard non-LED bulbs, and you don't have to replace the transformer just to add arectifier and a capacitor!
Not to mention that I still prefer the light temp and output of the G4 than the one of the LED bulbs.