This little circuit may not be any great innovation or a new invention.. but I offer it up here as an interesting and clever little idea and a quick and EASY little project.
I'm sure you all can modify it easily enough for different voltages and increased current.
So here it is:
Here's a nice solid, quick and dirty, (transformer-less) DC power supply that I built in just a couple of minuets.
It's a very clean and solid DC supply. The 6 volt output has extremely low ripple of less than 300mv p-p at a steady 150ma load.
I tested it under full load using a #47 bulb as a load for several days without a blip.
Nothing gets warm or changes value.
Safety:
Just be careful.
As with anything that has no AC power-line isolation safety and caution must be observed.
Good idea for those not into "Hoarding" like me, but no thank you, I have a grocery bag full of "wall warts", from 2.5V to 18V. Some transformerles, some not. From the educational standpoint, could be a worthwhile effort on a rainy day. Neighbors pass all their useless electrical hardware on to me. Need a vacuum cleaner motor or two. How 'bout some reformable Nicads, an old PC, or some hobby motors, but so far, no vacuum tubes. lol
marv
:I have been fiddling around with AC power dropper caps recently and did a few experiments for fun and knowledge.
:
:This little circuit may not be any great innovation or a new invention.. but I offer it up here as an interesting and clever little idea and a quick and EASY little project.
:
:I'm sure you all can modify it easily enough for different voltages and increased current.
:
:So here it is:
:
:Here's a nice solid, quick and dirty, (transformer-less) DC power supply that I built in just a couple of minuets.
:
:It's a very clean and solid DC supply. The 6 volt output has extremely low ripple of less than 300mv p-p at a steady 150ma load.
:
:I tested it under full load using a #47 bulb as a load for several days without a blip.
:Nothing gets warm or changes value.
:
:Safety:
:Just be careful.
: As with anything that has no AC power-line isolation safety and caution must be observed.
:
:
:I have been fiddling around with AC power dropper caps recently and did a few experiments for fun and knowledge.
:
:This little circuit may not be any great innovation or a new invention.. but I offer it up here as an interesting and clever little idea and a quick and EASY little project.
:
:I'm sure you all can modify it easily enough for different voltages and increased current.
:
:So here it is:
:
:Here's a nice solid, quick and dirty, (transformer-less) DC power supply that I built in just a couple of minuets.
:
:It's a very clean and solid DC supply. The 6 volt output has extremely low ripple of less than 300mv p-p at a steady 150ma load.
:
:I tested it under full load using a #47 bulb as a load for several days without a blip.
:Nothing gets warm or changes value.
:
:Safety:
:Just be careful.
: As with anything that has no AC power-line isolation safety and caution must be observed.
:
:
:
Yes Brian there is an image of the circuit shown at the bottom of my text.
Are you not able to see it?
try this link:
http://www.pbpix.com/radio/dropper%20supply.jpg
Wall warts can be bought a few bucks.
I bought a 3V-12V adjustable one at 1A for 5$ which is isolated, has less ripple, offers more current and is also more stable under load (taking into account that V/MaxA). Not counting that using such a simple circuit is extremely dangerous unless the circuit is encapsulated and offering a double insulated body like an electric razor (they used such a circuit for economic purpose).
Seriously, this is only good for curiosity.
Syl
:300mv for a 6VDC supply is far from being "extremely" low ripple. It's only 20:1 (-26dB)!
:
:Wall warts can be bought a few bucks.
:
:I bought a 3V-12V adjustable one at 1A for 5$ which is isolated, has less ripple, offers more current and is also more stable under load (taking into account that V/MaxA). Not counting that using such a simple circuit is extremely dangerous unless the circuit is encapsulated and offering a double insulated body like an electric razor (they used such a circuit for economic purpose).
:
:Seriously, this is only good for curiosity.
:
:Syl
:
:
::300mv for a 6VDC supply is far from being "extremely" low ripple. It's only 20:1 (-26dB)!
::
::Wall warts can be bought a few bucks.
::
::I bought a 3V-12V adjustable one at 1A for 5$ which is isolated, has less ripple, offers more current and is also more stable under load (taking into account that V/MaxA). Not counting that using such a simple circuit is extremely dangerous unless the circuit is encapsulated and offering a double insulated body like an electric razor (they used such a circuit for economic purpose).
::
::Seriously, this is only good for curiosity.
::
::Syl
Perhaps you two guys didn't bother to read exactly what I said as the FIRST line in my post:
"This little circuit may not be any great innovation or a new invention.. but I offer it up here as an interesting and clever little idea and a quick and EASY little project"
Yes I can read.
Syl
:
:Yes I can read.
:
:Syl
I am working on a pulse width soldering iron controller, and I need around five Volts to run a 555 chip. Since my chip will be enclosed, and operate a triac through an 1500 Volt optoisolator, there will be no danger of electrical shock. ihave been thinking of using one of the transformers lying around, but this circuit might just be the answer.
Lewis
A soldering iron element being resistive, you don't really need a 555 to create a PWM. A simple lamp dimmer will do as well. Unless there is some sort of feedbak sensor built in the soldering iron and used in a PLL to regulate the tip's temperature.
Syl
:
:A soldering iron element being resistive, you don't really need a 555 to create a PWM. A simple lamp dimmer will do as well. Unless there is some sort of feedbak sensor built in the soldering iron and used in a PLL to regulate the tip's temperature.
:
:Syl
I have a lamp dimmer device I have been using, but the noise from this thing can interfere with a 50kW station in Atlanta, about 25 miles away. The thing I am thinking about will make a click about every 10 se
conds or so. Beside, I have it on a breadboard, hooked up to a shop supply, and I like to see the bicolor LED I have on the thing go red and green as the triac goes from low to high.
Lewis
Agreed, these can be noisy (can we settle for a 30kW station?). But on the other hand, when I use my soldering iron, it is usually because the radio doesn't work...[grin]
Seriously, it is strange the dimmer I use (sold by Radio-Shack moons ago and designed for a soldering iron) creates so much noise, while my regular wall mounted dimmers do not affect my radios at all.
I have also an in-line dimmer with a torchiere lamp sold by Ikea and that one too is noisy like h***. Yet it uses the same components as the quiet ones. Could the grounded metal wall box help that much to filter the noise?
Syl"
:
:Agreed, these can be noisy (can we settle for a 30kW station?). But on the other hand, when I use my soldering iron, it is usually because the radio doesn't work...[grin]
:
:Seriously, it is strange the dimmer I use (sold by Radio-Shack moons ago and designed for a soldering iron) creates so much noise, while my regular wall mounted dimmers do not affect my radios at all.
:
:I have also an in-line dimmer with a torchiere lamp sold by Ikea and that one too is noisy like h***. Yet it uses the same components as the quiet ones. Could the grounded metal wall box help that much to filter the noise?
:
:Syl"
Syl:
I already have a box that used to be a time delay thingy, already has an AC outlet and an AC line cord, plus pots and a circuit breaker. I have all the parts here to build it, 555, optoisolator, triac, except for a power transformer, and even an old rechargable flashlight that has a 200 VAC cap to build Peter's madcap power supply.
So I'm ready to build a RFI-less temp controller, shoot, I even have some bicolor LEDs to show on and off. I don't even have to leave the house.
::
::Agreed, these can be noisy (can we settle for a 30kW station?). But on the other hand, when I use my soldering iron, it is usually because the radio doesn't work...[grin]
::
::Seriously, it is strange the dimmer I use (sold by Radio-Shack moons ago and designed for a soldering iron) creates so much noise, while my regular wall mounted dimmers do not affect my radios at all.
::
::I have also an in-line dimmer with a torchiere lamp sold by Ikea and that one too is noisy like h***. Yet it uses the same components as the quiet ones. Could the grounded metal wall box help that much to filter the noise?
::
::Syl"
:
:
:Syl:
:I already have a box that used to be a time delay thingy, already has an AC outlet and an AC line cord, plus pots and a circuit breaker. I have all the parts here to build it, 555, optoisolator, triac, except for a power transformer, and even an old rechargable flashlight that has a 200 VAC cap to build Peter's madcap power supply.
:So I'm ready to build a RFI-less temp controller, shoot, I even have some bicolor LEDs to show on and off. I don't even have to leave the house.
OOps, hit enter by accident. As to the metal box, I tried RFI filters, shielding, stuff like that, baut I think the thing converts all of the house wiring into an antenna, and while shielding and filtering did help, but there still was some RFI. I worked in a shop where there was a soldering iron that worked soomething like what I am building, and all you heard was a little click about every ten seconds. I didn't have to turn off the iroon to see if I had fixed a radio or not.
Lewis