CORRECTION to the video: on 12.45-12.51 I say that the voltage drop of the transistors are "multiplied" but that must be "added".

So each transistor in the Darlington adds its own voltage drop, for Silicon 0,7-0,8 Volt.. Sorry for the bad zooming in-out in the beginning.

I cannot help that. Made with a SONY DSCH 300 camera, all Sony camera’s are over-sensitive (my experience). Btw: I bought a new Full HD cam on 1 jan 2019 and will use it in the future..

I hope You Tube will make this video sharper, the Sony is 20 Megapixels, I don't know why the reproduction on YT is so poor. I have to set the camera to another mode, I think.

Much more info (variable Volt output) is here: [ Ссылка ]

Anyway: when you have questions about this circuit mail me on radiofun232@gmail.com. I will surely help you to make it..

How to make a good hum-free power supply. Long (instructive) video where all the issues and properties are showed (in real life, via a drawing) about how to make a good stabilized and hum free power supply for purposes between 12 V and 24 V or more/higher voltages.
More info here: [ Ссылка ]

For higher voltages: make a good heatsink when a substantial current is drawn (say: higher than 100 mA). Use HV transistors (with a good Hfe, say 50 x or more) for purposes above 60 Volt that can handle (if necessary) the current.
Circuit is not shortcut protected but gives an extreme hum suppression.

Some shortcut protection can be given by a power series resistor (5 Ohm-100 Ohm-10/20 Watt) to the collector of the transistor that does the job (here: 2N3055). In general: use a BD 139 (80 Volt c-b voltage) and a 2N3055 (115 Watt max.) as a Darlington. The 2N3055 mounted on a good heatsink, maximum voltage/current is in that situation 50 Volts at 500 mA and 4-5 Amp on 12 Volt. Resistor going from + (supply cap 4700 uF) to the base of the BD 139 (driver/first transistor) in the Darlington is 1 K5 - 2K7 at 12-18 V and 4K7-10 K at 18 V-24 Volt or higher.

I made this circuit once to supply a radio battery tube circuit on 120 V at 5 mA with adapted transistors, HV types. So you can go anywhere with this circuit, it will also work well on 12 Volt at 5 A (with a good heatsink for the 2N3055) but also on 50 V at 500 mA.

And it is hum free.

Go to 470 uF for the base capacitor of the driver transistor (BD 139-- driving the 2N3055).

Take in mind: safe supply voltages for the electrolytics, always 20 % higher compared to what they normally endure (measure it).

Better: 50 % higher (safer on the longer term, say 10-20 years). The price does not matter.

Fuses: depend on the power that the transformer can give, primary fuse must/can be quite high; when the primary coil is shortcut a big shortcut current will flow. So 1 A for small transformers in the 5-10 Watt range/3 Amp for (say) a 12 Volt-5A transformer.

First video about this circuit is here (not real life):
[ Ссылка ]


All the videos hat I have published on You Tube can be found via my Channel Trailer: Link is

[ Ссылка ]

In thematic order you can find these video’s under the “comments” section.

Important: to find all the links to the (+/-700) video’s on my YT Channel, select, in the comments section, “NEWEST FIRST”

My books about electronics are available via the website from “Lulu”, search for author “Ko Tilman” there.
[ Ссылка ]=

There is an important video via which you can buy a document where I give links to many of my video’s, published between 2010 and 2018.

Link is: [ Ссылка ]

My books are also available via Barnes and Noble and via Amazon.

Regarding all my video’s: I constantly keep them actual, so the original video’s with the most recent information are always on YouTube. That is the source, and search there. When my video’s are reproduced or re-edited on other websites/channels you can not (!) be sure about the original content (=really working electronics) and important adaptations to the circuits.
Be aware of that, I saw on the internet many of my circuits reproduced in a poor or even not proper way. I can not help that, sorry. Upload 28 december 2018.

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