Hero999

What package is it? How many pins does it have? It might be the same as the LM336. Reverse engineering part of the schematic may confirm this. http://www.national.com/ds/LM/LM136-2.5.pdf

You could replace the relay of course but I don't think that would solve the problem. Do you have a schematic? If not you could reverse engineer the part of the schematic around the relay. My guess is the relay limits the inrush current to avoid tripping the breaker. There will be a high power resistor in series with the mains inlet before the transformer. This limits the current from the mains until the filter capacitors on the DC side are fully charged. When the DC voltage on the rectifier rises above a certain threshold, the relay will turn on and short circuit the power resistor, allowing the amplifier to work at full power. There's probably something wrong with the circuit responsible for activating the relay.

Silly question but have you tried replacing the batteries? Even though they might measure 1.5V each on the multimeter, they could've gone high impedance and not be able to provide the current when the bug zapper is connected.

Click the Show unread posts since last visit on the main forum page.

It's basically a metal detector for which there are plenty of schematics on the Internet.

It's not necessarily a problem. The LM358 has many applications where its low speed is not an issue.

Wow, I've just looked at the datasheets for the transistors used and they're horrible! Their HFEs are low and saturation voltages high. I'd recommend using the circuit attached instead. The MOSFETs can be the IRF540N. Sorry the schematic is a little fuzzy, I can re-draw it more neatly, if you like. Here's a link to a much more complicated pure sine wave inverter. http://m.wpi.edu/Pubs/E-project/Available/E-project-042507-092653/unrestricted/MQP_D_1_2.pdf

Using a Darlington triple is a poor way to increase the current gain because it has a voltage loss of 3V or more at high currents. I'll post a correction tomorrow.

There are plenty of things wrong with that circuit. Your best bet is to buy an off the shelf inverter. Send to that, you should remove the LM324 and replace the old BJTs with MOSFETs such as the IRL540.

Please post a decent sized schematic. What do you mean by bypassed? If you remove one of the driver transistors the meter will only show half the voltage because the transformer is only being driven from half the voltage.

Why not use a CD4011 configured as an astable, rather than the old 555 timer? It uses much less power than the 555 timer and costs the same price.

Thanks for clarifying that. No hard feelings intended. I just disagree with you. You're the one who's being nasty. And for the record, you're mistaken, I don't think piracy is fine. I just think you're wasting your time.

Why not just use a thermocouple specifically designed for the purpose?

Let me Google that for you.

I read that post. What I don't understand is, how you expect us to help you when you don't say what your site is and that's before we discuss copyright or the technicalities of the circuit.

What does that mean? Speak English. You're just trolling now. I'm tempted to delete this thread or at least lock it but I'll leave it up to mixos (the administrator) to make that decision.

What does konfuciused mean? I've re-read the whole thread and have no where have you made it clear what your site is. All you've done is posted links allegedly containing illegal copies of your content. Please either post a link to your site and some evidence that it is your work which has been copied without your consent or back down.

Eventually, he makes it clear that his site is electronics-diy.com. Before that post we didn't even know which site is supposed to be the original. Don't worry, ignore him until he he can prove he's the original creator, otherwise he doesn't have a leg to stand on. Either way, I think the content should be removed, not because of copyright violation but because it's a very poor technical solution to boosting the current capacity of an LM317 regulator. A far superior method can be found on the on the top of page 17 of the LM317 datasheet. This can be improved further to boost the current more and include current limiting. People like this annoy me. If it were a computer program he'd written or a article containing original and informative content then I've be 100% behind him but it isn't. It's an LM317 regulator with an emitter follower connected to it; something which anyone with a basic level of electronic knowledge could've thought of.

And how much money do you think you've really lost? 1$, 5$? The only way to tell is look at your advertising revenue, which may have even gone up. Well, part of that statement doesn't apply to me as I don't live in the US. Whilst I agree with copyright to some degree, I think things have got out of hand. This isn't why copyright law was initially created. It's original purpose was to enable authors to gain revenue from their books being reproduced and has since been extended to include everything from music to computer software and rightly so. I don't have a problem with copyright but per-say but the way it's implemented these days is infringing on our freedoms e.g. you may be violating copyright law simply by playing a CD too loud in your car if you don't pay any royalties to the record company as its classed as a public performance. I've probably flouted the law hundreds of times by posting modified schematics in order to help people. So if that makes me a bad person, so be it. I suppose all I'm saying is relax, if you've got nothing better to worry about than people copying (not stealing) what you've decided to make public in the first place then I envy you. Besides, how are you going to prove you're the original creator? What's to stop them from claiming you copied them? If you don't want others copying your designs then maybe you shouldn't put them on the Internet in the first place? You haven't even posted a link to your website.

1) No. 2) Read the 555 datasheet and look for 555 timer tutorial on Google. 3) This is no a free design service. We won't simply design a circuit for you. The purpose of this forum is help people learn how to design circuits for themselves. If you don't want to learn then why not just buy an off the shelf timer module similar to the one i linked to previously?

As I said before, the capacitor needs to be enormous for that to work. What's the resistance of the relay coil? Yes, the capacitor obviously has to be in parallel with the power supply otherwise the relay will turn off as soon as the power is disconnected. Even if it's high resistance reed relay with a resistance of 1K you'll need a 22,000uF capacitor for it to hold for 20s and that's before the 555 timer's current draw is taken into account. You could get rid of the 555 and add a trimmer resistor in parallel but it will be less reliable as the delay will depend on the power supply voltage and temperature. What's the load current? A typical read relay will have a maximum current rating of 500mA.

Why bother measuring it? It's easier to read the datasheet.

I think you're looking at this the wrong way. No one is actually stealing from you. If someone steals your car you can no longer use it. If another person copies stuff from your website you still have it, you've not physically lost anything. Someone else maybe making money from your work but it's highly questionable whether you're actually loosing any revenue. If you were charging a fee to access your site, you could perhaps say that, otherwise it's doubtful, even if you do advertise. As far as copyright is concerned, you're probably right but I doubt it's worth perusing legal action as I doubt you'll get anything but I advise you be to seek help from a professional, if you're that bothered. I doubt watermarking would do much to deter people as it's easy to remove in image editing software. I've done it myself, but help someone with a circuit by annotating and improving it, rather than using it on my site. Yes, some of the circuits are of questionable quality. For example the 10A 1-30V Variable Power Supply with LM317 PSU is just an LM317 circuit copied straight from the datasheet but with an emitter follower stage on the output. The regulation will be horrible as VBE of the TIP41C can vary from 500mV to 2V over the temperature range and at different collector currents. http://www.utc-ic.com/spec/TIP41C.pdf

If you look at the circuit you linked to on this site's blog, you'll find it's the other way round here: we copied them, rather than the other way round. Are you charging for people to visit your site? Do you have lots of advertising? And if so do you really think you'll loose that much revenue from people looking at your circuit posted on another site, rather than yours? What if someone in China started manufacturing one of your circuits and selling it? You'd never know? Why do you really care? I'm happy for people to copy any of the circuits I post on my site. It would be nice to get credit but I couldn't care less if I don't.

http://datasheet.octopart.com/8600-0240-0000-Finder-datasheet-539064.pdf