Hi I’m Dave Jones here and this is the second EEV blog, the electronics engineering video blog. I had a ton of feedback from the first one. So, number two here it is. Now there were a few people who suggested that I change drab office background I used last time. So, here we are, we are at the bench. So, should provide some visual eye candy for people who want to be a bit distracted from my talking head.

First up we have a got a book review and as usual it’s a book of interest to electronics engineers. Now, this time I have chosen high speed signal propagation by Howard Johnson. His first book, high speed digital design, a hand book of black magic is basically is the industry bible on high speed digital design, transmission lines, stuff like that. So, if you into anything to do with high speed digital, you really should have a handbook of black magic. But, this one is the follow up to that. It’s the advanced black magic and it really goes in to more advanced topics and that weren’t really covered in the first book. So, it doesn’t really cover the same ground. It’s a complimentary book which supplements the other one. So if you have got that, I would highly recommend this and it gives you a great two volume reference set for signal propagation and transmission line design, PCB design and high speed digital stuff.

I have got a handy website for you. If like me, you spend half your day on digi key and mouser and find new websites just trolling for paths and you know trying to find the best price or the best availability and stuff like that, it can be areal chore. And it would be nice if there was a tool that searched all of them at once and luckily there is. And I use it like you know 10 times a day sometimes. It’s really amazing. It’s called findchips.com. And it’s a real basic website. It just got a single search window. You just type in the path number you want and it cross references dozens of different vendors and it gives you whether or not they’re in stock, price and all that sort of stuff and its real simple. There’s no fluff. There’s no ads. The guy who runs it is a bit of a mystery. We don’t really know. It’s just a contact us email. But its a fantastic site and I have never found it to actually be broken and I do know that the likes of mouser and digi key and the big ones do like to change their database access a lot. So, the guy has really kept up to date on searching for that info. So, give it a go. Findchips.com.

I have got an article in this month’s silicon chipmakers in April 2009 about this new project come up with. It’s really simple. It’s called the micro current and it fixes a major problem to do with almost every multimeter on the market. Now, I have really since I developed this little project, I have lost count of the number of people who have been baffled that their multimeter, even a precision Fluke 87 multimeter that they have been using for 20 years, is in many cases, useless at measuring precision current. Be it in DC or AC circuits and its do with burden voltage. Now, most people know about burden voltage. There’s a sharp resistance of the multimeter that drops a voltage when you pass current through it. No problem. Easy, right but most people think it’s really small. But its not. The closing you get to the full scale range of the meter, the bigger the drop, obviously. Now, a really good meter like the Fluke 87 V it will have, well this one actually has 1.8 millivolts per milliamp burden voltage. So if you pass 200 milliamps through this, if you try to measure 200 milliamps that’s a 360 millivolt drop. Now, it may not sound like much. But really, really 360 millivolts is if your circuit is 5 volts, bingo, you have already thrown your circuit out of voltage spec probably. Leave alone a 3.3 volt circuit or I’m working a lot these days on 1.2 volt circuits. So, you know I kind of like this. With a meter lie this, you really can’t measure precision current width. It’s crazy. But yeah, a lot of people seemed embarrassed that they don’t know that their meter is not very precise at all and that goes for virtually every meter in the market. There’re some that are almost in order of magnitude worse than this and price really doesn’t have much to do with it. You can pay $2000 for a multimeter and its still going to have the same problem. So, just be wary of it. Burden voltage.

Now it's time for chip of the week. This is where I mentioned a really handy chip for some other device and today it’s, not a chip as such. But it’s a range of chips in a technology called ANT. The website is thisisant.com. thisisant and the ANT chipset is basically a low power, extremely low power wireless networking solution. It’s primarily used in the fitness market for those chest transmitters that people wear. The ANT chipsets are a complete single chip solution that’s they include RF transmitter. They include the protocol stacking. You can set up private or public networks with these chips and they are quite easy to use and the website has a really good power estimator. So, you type in your parameters, what data at burst rate you want and it tells you how long your batteries going to last. So, they are really handy. They’re competition to this new low power blue tooth standard that’s around. now, ANT’s not actually standard. It’s more of a proprietary solution. But, Nordic semiconductor make the chips of those as well as the low power blue tooth standard and they’re worth keeping mind if you have got a really low power wireless transmitter which you need to implement. So, check it out.

Now, it's time for an equipment review. This is where I review a really cool piece of new gear. Now since the last blog I have been inundated, absolutely inundated with manufacturers wanting to send me all this new gear and well, they say it’s in the mail. So, I don’t really have anything new this week. So, I decided to go retro. And so I have chosen the Hewlett Packard 3478 A bench digital multimeter. Now, it’s an old model from the eighties. But it’s really nice. Its 5 ½ digits and its something like .004 per cent basic DC volts accuracy and its incredibly stable and you can buy them these days and be pretty much assured that its still going to meet all the specs. And it’s just fantastic. 5 ½ digits accuracy and you really can’t beat it. You can get it on EBay and all the other surplus places for not much money at all. They go really cheaply. I think I got mine for $150 or something like that. It’s quite cheap and they’re very popular and there’s a lot of them out there on the market. The markets flooded with them and really I think everyone should have ne of these. It’s on their bench. It really can’t beat having a really high precision 5 ½ digit meter on your bench when you need it. You wouldn’t use it for every day use. You would use your handheld multimeter for that because it’s more convenient. But, you really need, you really should have one of these. It’s got 4 terminal resistance measurement. It’s got rear terminals on the back as well which can be handy. Its main powered of course. I think there much even be a battery option somewhere. But, yeah it’s a really nice good a kit. I highly recommend you pick one up.

I forgot to mention one thing about the HP meter. Yes, the burden voltage actually sucks but you can’t have everything.