All You Need To KNOW About CROWBAR Circuits To FIX Stuff! How crowbar circuit works tutorial

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The Crowbar Circuit. What Is It? What Does It Do? This video came about due to some comments on an industrial repair video I made recently. A subscriber was asking if a diode on the PCB was a crowbar circuit. Not everyone seemed to know about this type of circuit, how to recognise it and what it does, so I decided to make a shortish video.
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Опубликовано:

17 фев 2023

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Комментарии : 455

@ThomasIngolstadt Год назад

I'm doing electronics on and off for nearly 40 years now, but never came across the term "crowbar circuit". Never too old to learn something new, thank you for this and all other vids you do, keep it up!

@jimmartin8853 Год назад

Thanks, good topic. As an old retired guy that worked as a tech in electronics since before white LED's existed, seldom have I found people that knew of this circuit. Most small commercial switching power supplies that I have evaluated in the last 40 years have had crowbar circuits on the outputs as standard. One issue I wanted to point out is that on failing power supplies, this circuit, especially the zener diode, is often the cause of the failure.

@mrtom64 Год назад

Well that had just about everything you'd want...good explanations, schematics, practical examples and demonstrating to destruction! Many thanks Richard, extremely helpful.

@jayjay6804 Год назад

I was introduced to crowbar circuits while repairing Astron linear power supplies. This circuit has saved many expensive pieces of equipment and is well worth taking time to understand how it works. Thanks!

@karlharvymarx2650 Год назад

I'm probably the slow kid in the back row of this class studiously eating his boogers but this is exactly what I need to see and presented in a way I think I'll remember. You often say while fixing boards that you learn to see the modules that make the whole circuit and that helps you see how it works. I'm at the stage where I recognize a few modules but it mostly is a confusing mess, so I really want to get to where I can at least see the most commonly used modules and make a pretty guess about the rest. Anyway, if doing more of these would hold back the rest of the class, just let me eat in peace, I'll figure things out eventually.

@hgbugalou Год назад

I am subbed to a ton of electronics channels, many focused on teaching. I must say this channel is the best for me learning wise. It's not overly basic nor overwhelmingly complex. You also explain things in very easy to absorb terms and at a good pace. I appreciate your scenarios are practical and easily applicable to the real world. You only focus on theory when it's important to understand for the given tutorial. Anyways, I'm glad I came across this channel! Keep up the good work.

@marknorton5951 Год назад

Useful topic. In a real world design, it’s very important the SCR cathode is connected directly to the supply ground and not via shared ground wiring. If it is, as here, the momentary high current can lift the ground potential and what you thought was always 0 volts isn’t any more.

@DeadCatX2 Год назад

"In a badly-fitted fuse holder I happened to have lying around" - I legitimately laughed out loud

@niallrobinson9225

You often say you are not an engineer. I work in an office full of electronics 'engineers'...you would put most to shame with your knowledge. Great videos 👍

@chris-sc Год назад

Excellent video! I really like your pedagogical approach. You start with a simple design, then formulate a hypothesis ("this component should blow when we add the extra voltage ..."), then test that hypothesis, demonstrating the expected effect, and then add a layer of complexity, i.e., the Zener. All this is clearly demonstrated on the perf board. This layered approach is great for people to absorb your knowledge step-by-step, and teaches not just electronics repair, but also design. Well done.

@paulmadsen51 Год назад

I'm really surprised how many people have never heard of an overvoltage crowbar. I remember seeing a great example circuit in "The Art of Electronics" way back in late 80's when I was a teenager. I've also owned linear regulated power supplies that incorporated the circuit in case of a pass transistor failure.

@guytech7310 Год назад

FWIW: An alternative to using a SCR (Thyristor) is to use a TVS diode, which is zener diode that can handle high current. TVS diodes come in Unipolar or bipolar (so they can work with AC power).

@CTCTraining1 Год назад

I’ve come across them a couple of times - well explained 😀👍

@smichels5117 Год назад

That's the BEST crowbar class I've been privileged to watch! Thank you! Great class, Richard!

@Stephens8x6Workshop Год назад

I am just a dabbler in electronics (home brew amateur radio) but this video, indeed all your videos are extremely helpful. Many thanks. All the best mate.

@dang48 День назад

23:37

@Sorarse Год назад

Never heard of a crowbar circuit, but this was an excellent explanation of what it is and how it works.

@ramraja7796 Год назад

Brilliant explanation , takes me back to my young days , you don't get guys like you any more who can simplify electronics as you do .

@ioannismertikas2920 Год назад

Brilliant explanation! The gentleman proved that he knows what is he talking about.

@bruzewill7081 Год назад

Thanks for the refresher of this simple & yet elegantly designed protection circuit. I'm a technician who has spent my career in the electronics QA department, two steps removed from the circuit troubleshooting / design of PCBAs. It's interesting to view these informative presentations.