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[@sdgelectronics]

PCBWay 3D Printing and Fabrication: www.pcbway.com/rapid-prototyping/ Picoscope 5000 Series: www.picotech.com/oscilloscope/5000/flexible-resolution-oscilloscope Support the Channel with Patreon: www.patreon.com/sdgelectronics

[@Duglum666]

Hey Steve, bit off topic, but: since your website is under maintenance: Is there any way to get the project files for your high power microscope light? Like the 3D Models, Gerber files and BOM? I'd really love to order/assemble one of these for myself. Thanks!

[@brianwood5220]

Enjoying this series Steve, thanks for sharing

[@ianhaylock7409]

I recently bought a "HLK-5M03 AC-DC 220V to 3.3V Step down Power Supply Module" (other voltages are available). This cost £5.00 which makes all the effort of creating a low power supply redundant.

[@vincei4252]

Kudos for running sus software from doddgy sites in a VM.

[@rwils6333]

There are special X2 capacitors rated for "In series with mains" use. Unlike the normal X2 thats rsted for only in parallel with mains use. For long term use id use one of those.

[@henrikjensen3278]

I would use a Hi-Link module, they are fairly cheap (A few $) low power SMPS modules and you can get them with a couple of voltages. HLK-PM01 is 5V 0.6A

[@bobert4522]

They really are top notch. I’ve got several of each in 3.3, 5, 12

[@mariushmedias]

There are high voltage linear regulators, like let's say LR8 or LR645 or LR745 from Microchip ... can do up to 450v input voltage, and a few mA of output current. If you don't have space for a big X capacitor, these followed by a buck may be solution (for example for the receiver... if it wasn't for the relays)

[@nezbrun872]

FWIW on a very similar personal project I opted to use miniature off the shelf "open frame" switch mode PSUs from Amazon, 5 for £4.49. Furthermore, I went for latching relays to avoid continuous drain. RS part nos SPST 3V 134-7910 coil 72mA @3.3V; DPDT 3V 827-6296 coil 229mA@3.3V

[@soothcoder]

What about using a big bipolar transistor with the zener used to regulate the base voltage? Makes a pretty basic voltage regulator.

[@SignalProduct-be2js]

10:23 - BJT in a common collector configuration acting as an Emitter follower - for the rescue!! )

[@artursmihelsons415]

Great video, as always! 👍 This reminded me MIG welder repair, back in days, who had capacitor dropper.. Old relay died.. After replacing with more modern one, I needed to recalculate all dropper circuit.. 😂 Pain in the b*t..

[@klassichd10]

For these kind of applications, I am using wall wart power supplies which I usally buy on a clearance sale. Good quality with all certifications needed but maybe not the very last quiescent power class. But the difference between 0.3W and 0.1W is not too big.

[@SeanBZA]

For receiver better to go for a higher relay voltage, you can see in all the PIR applications they use a 48V relay coil, so the current through it when energised can be low, around 15mA, but still capable of switching 10A loads. Then power regulation is done using 2 24V zener diodes in series, to spread the power dissipation, and often as well they use a trick and arrange the zeners to be 24V zeners, with a 3V6 zener at the bottom, and switch the relay using a PNP and NPN transistor pair, that shunts the relay coil across the 48V rail, providing power to the 3V6 rail, with a largish capacitor, so that the zener current or coil current is feeding the controller at all times. Just have to have coil current larger than controller operate current.

[@sdgelectronics]

I was considering this, but I think no matter what the power dissipation is the same unless the supply to the electronics is a switching regulator. The coil power is around 250 mW no matter what coil voltage. Unless you mean something different?

[@SeanBZA]

@@sdgelectronics Well you can have a small buck converter running off the 48V rail to drop it down, though often the simplest solution is a tint SMPS or even an iron core transformer, though losses in the cheap transformer might be the highest power use. Tiny SMPS though, repurposed cell phone charger, will be about the best bet, 5V at 1A, and with low standby power as well. Should be able to find a whole host of genuine Nokia, Samsung or other name brand ones easy enough, often in never used condition, or a 12V wall wart will work as well.

[@andymouse]

Interesting discussion....cheers.

[@TheEmbeddedHobbyist]

Squeak Mr Squeak

[@andymouse]

@@TheEmbeddedHobbyist Squeak !

[@TaggedElect]

I like simplicity of capacitor dropper and zener, but always end up with burned zener after a while. To gain simplicity and ease of use would recommend going with LNK302 from power integrations .

[@foobarables]

Any reason why the zener diodes fail? Because if you don't know why they fail, it will not help to switch to something like an LNK302. They fail too if not implemented correctly.

[@sdgelectronics]

2x designs coming up with power integrations controllers

[@IanScottJohnston]

1/2*pi*f*c.......Great to see these equations getting used. Cheers!

[@davefiddes]

Shouldn't your bleed resistor across the dropper capacitor be two? IIRC the breakdown voltage of most through-hole resistors is 250V dc.

[@sdgelectronics]

I think I picked out a physically larger 0.5W package, that had a higher rating

[@johnshaw359]

What about lipo/fe, buck/boost and solar-powered?

[@andyburns]

Latching relays instead?

[@Johadart]

Hi Steve, great video, may I ask what the name of the software you use in this, to show schematic and running the design? 🤙🏼🇦🇺

[@davefiddes]

LTSpice. It's a free download.

[@ulwur]

I scavenge mobilt phone chargers whenever i find them. High quality reliable 5v 2a PSUs för free!

[@Jkauppa]

manual dip switches are a thing, for a reason, no software required to operate a device

[@Jkauppa]

capacitive (mostly) voltage divider (C - C R series divider) is better

[@Jkauppa]

also takes care of any DC-bias, lets in only the AC

[@Jkauppa]

why would you push that much power through a zener/diode, put a resistor in series to prevent excessive power usage

[@Jkauppa]

that R4 resistor is suspect

[@Jkauppa]

take a look at my AC-DC power supply framework

[@vimalkumarkumawat7511]

Hello 👋 sir zee india 🇮🇳 .1uf 275volt &.33uf275volt capacitors powar line working systems explain 🤔 please help 🙏 thanks

[@allthegearnoidea6752]

I really wouldn’t use any capacitor dropper in anything with an external metal connection. In my experience they are very unreliable and provide no isolation and little protection against mains born transients, ok for crappy domestic product but nothing else. I think I would go as far as to say these are electrically bad practice given the low cost off power bricks. Having given you a bollocking I have used them several times in the past. Still you may well get out your system we have all done it. Great video as always regards Chris

[@TheEmbeddedHobbyist]

Like you say capacitor droppers are only really suitable for designs that can go in double insulated enclosures. No metal parts that penetrate the case also no wire coming out to a connector. great for low current circuits powered from the mains that can just sit there runnnong for years.

[@sdgelectronics]

I plan to have this fully enclosed with a pcb trace antenna. I plan to try out a few different designs though including non isolated buck and a flyback.

[@allthegearnoidea6752]

@@sdgelectronics well it’s great your experimenting I have developed similar designs in the past it’s the only way to learn.

[@BM-jy6cb]

Maybe it's just me, but the idea of using capacitor droppers for an ever increasing number of devices worries me, especially with the crap that comes out of China. It just goes against my sense of self preservation!

[@cmuller1441]

This is a terrible idea. Very dangerous: the antenna is connected to mains! And as explained the power efficiency is very bad... You'd better use a decent USB 5v PSU. If you are really on a budget, buy a 2nd had Samsung charger for exemple. Older ones are limited to 0.5A or 1A but that's enough here and they are basically free because they are too slow for modern phones.

[@sdgelectronics]

The design will be fully enclosed with a trace antenna. But the idea is to explore multiple options

[@Mr.Leeroy]

AP09N05-Zero