Common Chinese dusk switch. (With schematic.) 

I kinda miss the old bench. I like how it was gradually getting scarred from your adventures.

The new mat is nice, but if I'm honest I kindof prefer the old MDF bench -- burns & all (those gave it some flavor!)

All real benches have cuts, digs and burn marks, also SMD parts buried in the crevices - adds character!

Old bench was best bench. It was reminders of the good times, the bad times, the fiery times. It would be a good way to get new viewers interested in videos that left the biggest scars.

The old bench had "character". New mat is nice but please bring back the old bench top!

oh no what have you done thats like ashens throwing out his couch, you just cant do that

The old bench was heritage! It bore the scars of all those Big Clive episodes from the past, so I'm definitely in the "Bring the Old Bench" back division here! As for the 555, yes a rather vintage IC, and the first ever IC I used (Practical Wireless Metal Detector using a 555 as a tunable oscillator (variable R, constant C)). Maplin did a mail-order book entitled "101 Useful 555 Circuits" which is up in the loft somewhere - everything from kitchen timers (obviously) to model rail controllers / signalling controllers, Christmas Light controllers, and a host of other applications. Seeing as they are so cheap it'll be interesting to buy a bagful and revisit my mis-spent youth!

I've been using one of these for years. I'm using it to turn on a 10W LED flood light each evening :)

Hi Clive, thank you for all of your FINE work! Expat Australian retired in Thailand here, these "dusk switches" are everywhere here, mostly they work quite well. My personal experience is that "if they are going to fail", it will be within about 3 weeks. Have 3 of these in our home in Phuket, no problems. One that controls the night lights in our bathroom for the rescue poodles failed quite quickly. Replaced all fine. Really like the fact that these have a proper relay, other devices with triacs, or some such, do not work properly, we had to add a "real relay", for the LED lighting to work correctly, frustratinf, but now everything works. Love your videos!

Better background, except the two bright light spots - even zooming in washes out the top of the screen. Oh, and you're missing the "BIGCLIVEDOTCOM" - just in case I forget who I'm watching!! If the capacitor can be bridged, then I think I am completely misunderstanding the point of the capacitors - or perhaps zeners. Is there any chance you could elaborate?

Hi Clive, I've been using a 12v version for several years to control our solar powered led illuminated street address sign. Was very interesting seeing what's inside and how it works!

I like the bench. It has character, and shows the scars of the adventures you've shared with us, the fortunate viewers.

Thanks, Clive, when you said 'common collector' in the description of the circuit it reminded me why the supply rail tends to be labelled VCC in bipolar transistor circuits, and why it's labelled VDD in FET circuits. I've been thinking about this for a while since my memory started failing.

Well, that specific 555 timer is intended for the *Chinese* versions of fingerprint and iris bio readers. in which it's the only component and just unlocks them 3 seconds after you press the button.

The scorched and stained desktop has character, no glare, and is the BC trademark. Much better for video than the New Improved Model (R). // Good old 555's; those claims on the data sheet are quite believable, because those chips used to turn up in the most unlikely of circuits. I've even seen one being used as a local oscillator in a home-made radio receiver. Tough little beasties, too.

I first used 555 timers to time my ham repeater builds in the later 70’s. To get stable repeatable timing, tantalum capacitors were used. Teaming these up with cmos gates it did a basic but pretty good job. The 556 is the dual device, with two timers. I have A 555 cook book there are all types of circuits, blinkers, oscillators. It is a very versatile device.

I have been using 2 of these for over 3 years now every day to run about 50-60W of lights from it for my backyard and my parents backyard. Installed once, never touched it again... works like a charm.

Clive, back to the pressboard benchtop, please. The grey is unpleasant and the glare is yuck.

I'd prefer the old one. Less shiny, less crowded.

I was kind of excited to see the 555 timer show up in a video. Was my first IC I played with when learning electronics and have always been curious as to how many current engineers grew up playing with 555s. Still have my original timer cookbook before the days of the internet. I would have to admit, was sadly disappointed seeing the comments were dominated about the bench. Was hoping to read some good timer flashback stories. Oh well...my two cents. It's human nature to hate change when ones in their comfort zone. So the majority will want to keep the density fiberboard. I'll vote for that too.

I was giving this a good, hard think. On the one hand, if you can fix the lighting with some diffusing film the cutting mat background is alright. It's clean and simple, and auto-focus takes well to it. On the other hand, the bench... it has a story. The markings on it are all from different misadventures and represent everything you've done so we didn't have to. So it's a matter of being modern and looking like every other smart RU-vidr or going with your own "Aesthetic:, no matter how it looks.

The old bench has character. I don't mind you using this mat though, so it's up to you. Ahh, the 555. The holy grail of cheap, versatile ICs. I honestly don't think that little chip is going anywhere any time soon; it's just too damn useful.

Is the relay coil really connected before the 100 ohm inrush resistor? The poor coil will see 325V spike when plugged in. This can also damage the output of the 555.

I graduated electronics school in 1978. I'm loving this. I can do all the new hi-tech stuff, but old discrete circuits are fun. There aren't many people that can do this anymore.

always fall asleep with late night Clive... not because it's boring... but his voice is so calm! relaxes me! love this, never stop please

When I was MUCH younger, we always called the mains quick connector A MOUSE TRAP. Very common in factory's in UK..

Thank you, Clive, for this teardown it has got me the circuit I needed in a roundabout way. This may interest people and hopefully, Clive or someone much smarter than me can figure this out and why it happened. I copied this 555 circuit down, I require a 12-volt photocell circuit so I removed the mains section. I took an old 555 and installed it on a test breadboard, I replaced the relay with a P-Channel Hexfet IRF9540N taking pin 3 of the 555 straight to the gate and using a 1Mega Ohm gate resistor connected to +12v. At first, I used a typical ORP12 type LDR, but on swapping this to a scrap component which I believe to be a phototransistor it worked fine with no component adjustments. Now for the interesting bit, I powered a tiny screw in mini 12volt bulb from the Hexfet and the whole thing was running from a Lead Acid battery, so plenty of current available. I wanted to load test it, so I stuck a 50 watt 12-volt Halogen bulb across the existing bulb, it did not light properly and the small existing bulb went dim, the 555 began to overheat??? even though it is not involved at all in powering the load. After quickly removing the supply and allowing the 555 to cool down, everything works perfectly again. I now have two 15 watt 12-volt screw in bulbs, so a total load across the Hexfet of 30 watts, I am actually quite happy with this, but I am still confused as to why the 555 got hot when I stuck the 50-watt load over the Hexfet. I can only assume the heavy inrush to the halogen made the supply rails fall too low for the 555 to function correctly. My knowledge of electronics is not fantastic, I do not do enough to get really clever at it, to me it is a tedious means to an end, supplying me with useful circuits to do the home projects I may find difficult to buy off the shelf circuits for. So any answers would be good, I am always curious about why some things happen. UPDATE, the issue I am assuming must have been supply rail related because rightly or wrongly I seem to have solved the issue, I have fed the 555 through a 1N5001 diode and installed 3x 5.5 volt 1Farad storage capacitors in series to create a 1farad 16.5volt capacitor instead of the tiny supply decoupler of 50uf that I had installed, thus giving the 555 its own virtual power supply. It can now switch 80 watts of power, yes the Hexfet starts to get a bit warm, but nothing a large heatsink would not sort out.

I signed my soul away to Wago 5 years ago and have had no regrets. This message is sponsored by Wago.

I bought one of these from eBay/China but the 12v version. I use it to turn on/off my LED down-lighters on my garden room. The sensor it on the inside, facing out of one of the windows. Had it for a few years now, works perfect!

"secretly you're hoping it does go bang"....no secret here. I like it when things go bang.

I have been using a 12V version of this for some time to run a short piece of waterproof LED tape in the porch. I expected water ingress issues (as I did literally just screw it into the porch trim) but so far its been working fine. I did wrap some amalgamating tape around the screw holes and where the wires go in, in the hope it reduces the chances of water blowing in. The water has only been an issue in the junction box as I foolishly didn't drill a drain hole in it. Really the only issue I have is the lights come on when its not yet dark enough to get any benefit, so I was quite excited to see this video to confirm where I need to be looking to fix that.

Old bench is traditional. Also this one seems to be causing autofocus issues? (this mat is basically a big version of that AF cheatsheet you had...)

Mat or no mat, keep making these vids, for someone who knows nothing of electronics in the detailes this is fascinatiing to watch and follow, and most often eeven learn something.

I have a Twist Lock Photocell that powers a 400w Metal Halide Streetlight. Had it for 5 Years now. Never failed me. its still Outside today, powering that very same Streetlight. the streetlight itself is 15 Years Old. Lamp needs replacement, still works, but the lamp now has a very strong Green tint.

I just received a pack of 555s from eBay for some breadboard projects - £0.76 for a pack of 20. The are great wee chips and so easy to use. Oh, and I prefer the old bench. Each burn and scorch mark tells its own story.

4:32 - "...secretly you're hoping it _does_ go bang." Me: _sheepishly looks away from monitor whistling innocently_ :)

The new mat is too busy.

I was using a dmx dimmer and there was a snubber network on the outputs, which caused the led christmas lights to glow. Plugging in an incandescent night light of 7w fixed that, painted the bulb black to kill it's output.. worked a treat!

That was really neat. It was quite similar to the ones we install for lighting controls in the field.

Nice dusk switch, I like how easy it must be to convert it for using it with 12VDC only. If you don't trust it on mains voltage or want to play around with it safely, you can always put it on the secondary side of a low voltage power source for e.g. led lights. just (remove and) bridge the X2 capacitor. Optionally you can remove the bridge rectifier, too, but it take away the "universal" polarity power input "feature". Now that I have read the video's description, I read that you can buy the 12VDC version as well. I wonder what the difference is...

I have the 12v version of this for backup lighting during power outages; it works quite well. Old bench!

Got one of these 3 years ago for $1.99 sod knows what it was in Sterling. Out of sheer bloody minded curiosity I put it outside mounted to an IP65 box in which I stuck the connections using wago clips and it controls a 30W LED Flood. Mounted BLUE end UP.. Still reliably running today ! Laughably it has outlasted 2 propper photocells running the same type of light ? You can get 12 and 24V versions.

I prefer your old bench, mainly due to the reflection from you lamps. I just started making a few RU-vid videos it's more of a video diary really. Anyway it's much harder in really life than I thought it would be. Always enjoy your stuff. Interesting comments about LEDs and snubber, I have had a lot problems with ghosting on early LED installations, I double cut now. Regards Chris

These "dusk switches" work great on 12 volts. [solar powered barn and garden lights]

Dear Sir, Good day. I am a mechanical Engineer but interested in electronics . Your video had helped me to repair an exactly same dusk switch from China. Thanks and best regards, George A P(India).

I actually like the look of the cutting mat, and the "glare" near the top of screen does not bother me, BUT as you and I both know you need a surface that is fireproof, chip resistant, non-skid, non-conductive, non-reflective, non-staining, scratch resistant, gouge resistant, easily cleaned and easily disinfected. * I'm not sure there IS such a material. * Explosion proof would probably be a good thing, too...

Thanks Clive! Exactly what I would have needed for the LED flickering as I discussed on the discussion thread. I did change the unit for another DTD sensor and there is no flickering. The one I used from "Greenbrooke" is the type used on the top of UK street lamps. It's big. It's not particularly attractive, but it works! I might just buy a couple of these as shown in your video to have as spares. Excellent tuition video, thanks.

Hi, Clive. Many many years ago I had to make a very simple temperature controller with the parts I had available. It was to keep home photographic chemicals at constant temp. I cobbled up a circuit not unlike this one, thermistor instead of LDR. It worked so well we were still using it 3 years later when we changed to different process. Tom...

Thanks Clive, for another excellent video with good info...and the unit under test was actually a pretty decent little device! I was semi-impressed with the size of the relay after you opened the unit...it probably is actually good for 10A load!...and was rather surprised (like you) to see a 555 timer chip...before you reverse engineered the circuit, I thought that might somehow be used for the delay, but the circuit design is actually brilliant...it uses not the timer function of the 555, but the threshold sensor and output switches of the cheap chip! I too would add a snubber diode to protect the chip's output transistor. As far as the applications of Fingerprint, Biometrics, RFID...those are just "new", and more current and stylish circuits being designed...I too can't immediately imagine where a stand-alone timer could be used in applications which undoubtedly have processors, which have all the internal timer functions one would ever need, but that's the beauty of the manufacturer putting that into the chip data sheet...they don't have to figure out how to work it in...they leave it up to designers to rack their brain to figure out how they could possibly design a 555 into those applications...sort of like the manufacturer of a bicycle telling NASA there's an application for it on the space shuttle...actually a rather brilliant marketing strategy! New table mat looks good but I agree with others, its too busy, it hijacks camera focus, and lacks the well-earned character and patina of the old MDF, not to mention the official BigClive ID. I think you should have a marker on each blemish/burn-mark, which links to the video in which it was created...you could call it: Big Clive's table-top archeology. Cheers from Connecticut!

our old guitar tech used to hit these mats with several layers of a flat clear spray paint, since his work place was usually bright. helped him not get those visual anomalies after staring into a bright light. Maybe that will be more friendly to the camera too.

I prefer the old bench but think it is worth pulling out the mat in some disassembly steps. The main issue with it is the glare, putting the same markings on the bench or sorting out the surface/lighting to reduce that may be enough to help. I am not sure if I am the only one but I also find it a little disorientating when the camera is zoomed in, but its not enough to stop me enjoying the videos.

Used a 240 volt one on a 30w LED for 5 years still working well, Having said that, now it will probably fail.. BUT - The 12v ac and 24v ac ones are the same with a couple of different supply components. Amazingly reliable for a cheap piece of tech from china

Needs a Big Clive sticker on it!

Strange that the relay doesn't have a back emf diode across the coil. Some relays have a built in diode but checking the data sheets for that LS-T73 relay, it doesn't seem to have one. I had to listen to the end of the video twice. Clive said something about shorting out the dropper capacitor. Something would pop and let all the magic smoke out! On the second take the bit where Clive said bypassing the capacitor would let the circuit run off a 12 volt supply sunk in which makes sense. With a capacitative dropper it is usual practice to add a high value discharge resistor in parallel with the capacitor to prevent electric shocks but this circuit is intended to be hard wired to the mains so it's not going to be unplugged. There is no surge limiter/fuse resistor in series so if the dropper capacitor were to go short circuit it would fail big -time.

A tip for those who want to play with timing capacitor values in this circuit, if you want time delays of 30 seconds or more, for reliability the capacitor should be a tantalum capacitor, as it will maintain its value for many, many years over a wide temperature range. Electrolytic capacitors dry out over time and become electrically leaky to the point where they'll never charge up, so the time delay in the circuit will become longer and longer and eventually will never time out. The 555 timer is very nice for its simplicity and economy of peripheral parts, but to get very long time delays with cheap components, nowadays I would use a digital counter chain with a low-value ceramic capacitor as a timing element.

Like many others here, I prefer the existing bench. The lines on the mat and the glare are kind of distracting. The solid color of the bench (even with its battle scars) makes a nice simple background and makes it easier to focus on the components you're showing off. Have you thought about maybe sanding it to remove the burn marks? You could save the mat for special occasions when it could be useful.

13:43 My guess is that they are relying on the fact that the 555 is a push-pull output. Still though, I'd be a little worried that the push-pull output's dead-time would allow for enough inductive "kick" voltage to build up, but I don't know for sure. I'd imagine it can switch fairly fast so yeah (the claim of microseconds timing in the datasheet) ... a diode simply may not be needed!

I much enjoy the Matt in the video. I feel it makes it easier to follow the item in better focus to the eye. 👌

Sorry Clive, bring back the MDF. Not sure on the cutting mat.

funny story, I was picking up a cliff unit to use for mains stuff based on the videos you make, the amazon listing in the us has two reviews giving props to Big Clive. pretty cool stuff sir. needless to say it was 20usd cheaper on ebay. And the 555, when I think about it, its a hysteresis device to me. so much to say, never knowing when to say it. cheers.

The snubber diode is not required. The 555 output is a totem pole type. When the output goes high there is a PNP transistor shorting coil to the 12v supply. Amazing use of s 555 as a window detector and latch.

I've gotta say, I'm casting my vote for the old workbench. While I find the contrast of the gray of the cutting mat pleasing, (a slight drop in lighting level would probably work out better) yet the grid and concentric circles are really distracting and your autofocus will try to focus on that instead of what you're working on. Unless you're planning to add your own version of "FOCUS YOU FACK!" to your videos, and if so, then ignore that. As you mentioned, the glare from the lighting is atrocious. But, you know lighting far better than I do, I'm sure you can work around that. ;-) Do you find the darker color easier on your eyes when working? That's another factor to consider. Last thing you need is to be playing around with mains voltage with eyestrain! Gotta release the magic smoke safely, after all! The old workbench, while not providing as much contrast, is definitely a recognizable element of your videos, and has the "battle scars" of various explodey bits, spilled flux and alcohol, and is just as much a part of the Big Clive experience as you are! I suppose, you could also get a new piece of MDF, paint it a matte dark gray, and start a whole new workbench to blow stuff to bits on. I also like the pink/purple cutting mat... I'd get it for the purple side if I had any use for a cutting mat! It's purple, without being... Puuuurrrrrrrrplllleee. LOL

I like the battle scars on your bench surface. We can only hope for more.

Ah the good ol' 555! I'm surprised that the voltage at the relay coil isn't enough to damage the chip's output transistors, since one end of the coil is connected to "rectified mains", I know the voltage on the DC side of the rectifier wont actually be anywhere near mains voltage but still a little weird in my opinion.

I use 2 of those to control the lightning in my garden, each one control 2x 220v Lamp, and 1 control an COB Led 220V at the porch too. They are very interesting. I know not the best engineering, but they do the job!! As Clive mentioned they are not instently, about 5-10 sec, but I dont mind that. I need them to turn ON light at night, and Off during day and they do that pretty well 😉

Bring back the bench! The reflections and shadows on the mat are ghastly! PS. I have an "antique" quicktest branded RS with Red Black and Green which belonged to my father before me.

... Hi Clive ... ... If U can remember some part of IE: a key word ... ... If you Press the "Ctrl" button bottom left of the keyboard ... ... While holding that ... ... Then press the "F" button ... ... A pop up window will open ... ... In my case a small menu bar ... ... Just type in the search box your key word ... ... And where if it is on that page ... ... It will show all occurrences if any ... ... Also as you type it will start looking and ... ... Highlight them in Blue at the same time as jump to that word ... ... If there are more than one the other will be in yellow ... ...

I think the cutting mat is fine but the scarred worktop surface has its own character. I suppose you could always just switch things up whenever necessary or if you happened to feel like it, though.

I made the dusk switch based on your schematic.works very well.thank you.

I love the new mat, makes your videos look much more classy and old bench makes everything look grainy and stale, maybe a compromise like a painted bench, I agree all the lines are slightly distracting but no more gross MDF pleasee!!

These units are sold in South Africa under the "Major" brand name. I had one survive 2 Cape winters driving 2 LED outdoor lights with no problems with water ingress. Ants got the better of it this (the 3rd) winter. 220v loves to pop all the copper tracks off the circuit board! Funny enough, the 25A unit, which is somewhat larger physically that this one, is quite a bit cheaper... This vid reminds me, I better get the silicone out to stop the ants getting in.

The problem with the new mat is, that it is visually distracting, making the screen much "busier" - and it is also adding quite a few reflections. The old bench had the benefit of being just a plain, boring surface. That is not to say the mat should go entirely, but put it under a transparent, slightly dark, non-reflecting plastik (like one of those thick rubbery surface protectors). This should reduce contrast, reduce light reflections *and* protect the mat from the inevitable fires and explosions.

Aluminium wiring was common in Canada for a while. The issue is doing work now requires converting between aluminium and copper which can't be done directly. I can't remember what the transition metal is. If the termination is not done properly, it can explode, as happened when a backup generator was switched on during a UPS test in a data centre here, sending shrapnel flying.

I like the grey mat. Gives you a sense of scale to the objects displayed. If only the lines would be paralel to the frame.

I prefer the old workbench. It was showing scars of your previous conquests and issues. You need to get a tattoo on your hand or your fingers with big clive lol

One thing that strikes me as odd about this circuit is that with the relay tied to the unregulated side, that's going to connect the output pin of the 555 to the unregulated voltage (though the relay coil). Generally, connecting any pin to a voltage higher than Vcc is a bad idea. I looked at the spec sheet, but couldn't see anything that put limits on what the chip can sink in the high state other then the absolute limit of 225mA.

Bring back the old bench please, Clive. This one is way to shiny, plus the old one had a much warmer look to it. Plus of course it showed it's history!

Clive I've got the 12V version here and had no dramas with it in over 18 months of daily running and the circuit is the same without the capacitive dropper

I have a 12VDC version of this that has been switching my 12V LED lamp post in the garden for over 3 years now. It's never missed abeat. Got in munted in the window of the shed due to the flying leads.

I bought one exactly like yours on Ebay from China for $2.76 including shipping. Amazing they can sell them that cheap.

Good presentation,thank you. Amazing least to say of many fans think that bench cover is so vital And not one single comment regarding Electronics!!!!. May be one or two!!!!!. Guys this is not a movie it is Lab Test.

I prefer your existing bench Clive.

the old work bench is iconic , like 'Ashens and his brown velvet sofa .... the fans like continuity :)

The mat awesome but the two shiny spots are ruining it.

Vcc isn't "voltage common collector" it's just the collector supply voltage. It's usually positive. Vee is the emitter supply, usually negative. Vbb is the voltage that would be at the base if the base-emitter current didn't drop that (actual base voltage is Vb). Vdd is drain voltage of a FET (usually positive), Vss is source voltage (usually negative) and Vgg isn't really used since FETs don't have high enough gate current to matter. In a circuit with multiple transistor types one does not use separate rails for P and N types, so for a PNP (or P-channel FET) Vcc is positive and connects to the emitter, while Vee is negative and connects to the collector. I say usually a lot there. It's nearly universal. But if you've got only P type devices you might label the rails as Vee (or Vss) for positive and Vcc (or Vdd) for negative. This pretty much never happens. TL;DR: Vcc, Vdd = +V. Vee, Vss = -V.

Aw I quite liked the old bench. Although the pink cutting mat does make me very happy

I remember doing systems and control technology in school in the early 90's and the 555 timer chip was the very first chip IC we learnt about in detail. We used it to flash a strobe and sound a buzzer in an alarm circuit. We did loads of work on logic gates like the 7404 and 7408 to but i rarely see them in anything I open up.

the beat up bench just has more character. good video regardless

I like the new background of the cutting mat.

The new mat gives some sort of size-reference even when the camera is on full-zoom, but the old bench seems more authentic. Mix and match maybe depending on what you are filming? Also I like the way you describe how to reverse engineer PCB's, great idea that I will try myself!

I am still glad what you do we all get something from it from your sacrfice.

Hi, the old bench looks amazing. It does not bounce the light much and its a kind of neutral colour as well. The grid lines in this is causing a confusion when you show small parts on top of it. But hey its just my humble opinion :) Love your videos. Keep it up.

Well, I'm just going to have to make one of these! I have a pack of the 555 timers I bought a little while back. So you said that by removing the smoothing capacitor, the circuit will run on 12 volts??

555 timer, applications: fusion reactors, warp drives, Terminators

Great video. However, the lighting problem is simple an angle of light to camera that needs adjusted. Usually have lights at 45 degrees to camera, so that the light bounces off at 90 degrees (45 degrees of the other side to the camera) - but with that surface, you may still get a little problem.

I melted my cutting mat by way of a triple array of tealight candles which then liquified and became an inferno. Thank goodness I had some quartz sand nearby.

Bought a couple of 12V versions couple of years back, came with wiring details + easy to Google, the 100K was a POT to adjust light on/off level. The white (clear) box goes upwards just put the wires into a terminal block in a small weather proof box with plenty of sealant.

well glad to hear you hadn't burnt to a cinder, love the grey matt apparently blood shows up best on a grey back ground so the movie special effects people say !

The "applications" for the 555, I think they might be used for the "dead time" between reads.

Someone did a study and the best BG color for displaying items was a light, bright shade of blue. I like the grid lines but I don't like the slate color. It's hard to tell because the reflection is quite distracting.