Recent Posts

Pages: [1] 2 3 4 5 6 ... 10 Next
First I wasn't so glad of the idea, since I can't know if the setup could hold all the weight.
Or if I could make it, since it is a little my advance than what I was thinking.

But then I made a 3D model of the project and saw how unsecure the design was, when you compare it to the scissors model.
Wether it can hold the weight depends on how sturdy materials you choose.

With a bunch of math you can analyze how the forces are distributed.

Design for a higher weight than expected and add some extra tolerance to the parts and things should be fine.
Beginners / Re: Problem (?) with simple op amp circuit
« Last post by Asmyldof on Today at 01:07:07 AM »
You are forward biasing a transistor in your feedback loop. That is possible, but it does require some care and attention to prevent hinky oscillations, something like those oscillations might be a cause for dead op-amps.

Another cause could be current drain at the output in case of sudden input voltage increases, though I'd expect that to be of such short duration that it wouldn't cost you many op-amps in a single go.

A reason for Q2 to break would be high dissipation, 6.8V across 100ohm is 68mA. if your supply really is 20-ish volts, that means the transistor is "eating" about 13.2V, because, where else does it go? That means it dissipates 13.2V * 68mA = 890mW.
If it's a normal TO92 type that'll very likely kill it, even soldered into a PCB, when working in a breadboard (are you using one?), it's anybody's guess. (Because the heatflow in a soldered situation can be predicted, in a breadboard that's significantly harder).

As a side interest, if you've destroyed one part, you might want to change the measurement points and types a little and try again, but when you've destroyed two parts in the same set-up, that's usually the point to critically examine the construction and/or schematic.

Q1 could be having problems with base currents in case of oscillation or spikes on the input, but with a 741 it seems that one is reasonably safe.
General Chat / Networking hardware suggestions?
« Last post by steve30 on Today at 01:05:42 AM »
My Mother has set up a wireless network, with internet access downstairs. Upstairs I have my own private network (currently just wired stuff, but I've sometimes used it with wireless stuff).

I need my private network to be able to access the internet connection which is present on the downstairs wireless network. Using hardware available to me, I set up a Windows 2000 laptop, with a wireless card. This connects to the downstairs network, then Windows 2000 shares this internet connection to an Ethernet card, which is connected to my switch.

What kind of standalone hardware did I ought to get to replace the laptop with internet connection sharing? I'm not sure if I just need a bog standard wireless access point, or something else.

I've shown the setup in a diagram (attached).

Test Equipment / Re: Teledyne LeCroy WaveRunner 64xi
« Last post by nctnico on Today at 01:05:24 AM »
I would not be so sure about the lifetime of an SSD. The guaranteed data rentention time of many SSDs is 3 months when powered down. No this is not a typo or a bad joke; it is actually in the specs! I got a  big :wtf: moment when I found out.
General Chat / New Iron
« Last post by TorqueRanger on Today at 01:05:11 AM »
I am looking to sell my Weller Wes51 cause I am not liking the tip selections and setup and I love using my Hakko better  .. I was looking into buying a Used Hakko Fx-888 or  Hakko Fx-888D .. Do you guys have any suggestions for about under $100 bucks???
6 sell UP! filament in several colours including white.

The (manufacturer) website also has a list of regional agents. If you Google for 'UP! 3D filament' you should find it locally.

Test Equipment / Re: Flir E4 Thermal imaging camera teardown
« Last post by Bud on Today at 01:01:56 AM »
As i said i used VirtualDub to record my videos.
I think codecs may need to be installed separately and i used couple generic codec packages from the Net.
Nice. I hadn't expected it to look bad. Not sure what the other guy meant with his comments about that it would look like "shit" or "spaghetti". I guess perhaps he wouldn't know any better considering he's a guy who prefers not to take things apart, but turn them on ;)
General Chat / Re: Special Price FOR EEVblog Members
« Last post by Garnet on Today at 12:57:32 AM »
Looking to buy some test gear from TEquipment.
Could someone please send me the discount code?
Thank You.

PM sent.
Repair / Re: Yet another Tektronix 468 repair
« Last post by JacquesBBB on Today at 12:52:05 AM »
I have started to dismount the attenuators,  but with  precaution.
I looked to the 100x attenuator, and it seems that one of the contact of CH1 is always open
while it is always closed in CH2 (the good one).

Is this part of the problem ?

If it is, what should I do ?  I try gently to push it down, but it seems to be stuck.
Pages: [1] 2 3 4 5 6 ... 10 Next