Recent Posts

1

Beginners / Re: good/cheap headphone aplifier/dac?

« Last post by flaotte on Today at 10:51:42 am »

If you like the Bose QC25 why not just buy another?

I want to get a bit better DAC or amplifier. Sound goes worse on higher volumes for my source.
I switch between work/home computer maintaining same docking station, bluetooth would add extra hassle. USB->wired solution works better in my case. Will check CX31993/ALC5686.

Regarding headphones, QC25/35 can be can a decent candidate, really comfortable.
But it did not last that long. I don't want to support business that produces short lasting products. In general I like good quality items and I take care of it.
if it looks like that after 2 years  (not my link https://preview.redd.it/my-qc-35-ii-started-to-fail-apart-badly-v0-oz75wugeb8z91.png?width=1080&crop=smart&auto=webp&s=75cc96a2f429a9436636e750d85929db98b348fd) there is something wrong with the material, I would say.

2

Repair / Re: ES120 Electronic Screwdriver repair

« Last post by TorP on Today at 10:49:59 am »

Hi! I had a problem with my ES121 motor. It was drawing well over half an amp with zero load (connected to a lab psu). I opened it up by bending the metal tabs on the side and inspected the commutator under a microscope. It turns out there was metal filings in the gaps of the commutator. I cleaned the contacts with a glass fiber brush and that solved the problem. I wanted to share this if others have the same problem

3

Beginners / Re: Building instrumentation amplifier for PT100 sensor

« Last post by bborisov567 on Today at 10:49:01 am »

@mikeselectricstuff - I started doing the calculation - scaled the LM334 resistors for 1 mA and got to the bridge. Then i found out that with 1 mA excitation current and 100 ohm resistors i already get 0.1V/C from the bridge. Now i start asking myself - is there a point for an op amp since I will be feeding the output of the bridge to a multimeter which is going to have 1 Megaohm input impedance at worst. Except for linearization is there another reason to use op amp? 

4

Beginners / Amplifier type

« Last post by elki on Today at 10:47:56 am »

Would you consider this amplifier to be of the voltage-feedback type or the transimpedance one? If I am not mistaken, this configuration should work as a transimpedance amplifier with the gain I(R2)xR1?

5

Projects, Designs, and Technical Stuff / Re: Suggestions for secure authentication solution?

« Last post by mikeselectricstuff on Today at 10:46:13 am »

Microchip SHA104/SHA105 and ATSHA204 look interesting from the cost point of view ( £0.30).

Having looked at a few devices now, seems pretty much any crypto chip can do the job so I think I'll explore these to start with based purely on cost and availability.

The latter looks like it has a full datasheet available, so will read through that & see if I can get my head round this...!
 

6

Other Equipment & Products / Re: barely used Quickoo T12-945 died during heavy soldering

« Last post by elektryk on Today at 10:44:38 am »

First thing that you can check is MCU supply, another one is mosfet (but with burned mosfet display still should work).

7

General Technical Chat / Re: Does the electrical grid acompany network lines?

« Last post by Ian.M on Today at 10:43:37 am »

https://www.ecmag.com/magazine/articles/article-detail/systems-fiber-optics-energy

8

Test Equipment / Re: Racal Dana 1998 blown fuse in BNC connector

« Last post by TERRA Operative on Today at 10:41:30 am »

HP 5335A counter uses a similar fuse-in-BNC setup on the 3GHz input option. I used the pico-fuses and it was a peefect fit.

9

Other Equipment & Products / Re: Helping picking quality flush-cutters (Knipex vs Ideal-Tek) ; Steel vs Carbide?

« Last post by elektryk on Today at 10:39:14 am »

I've got Piergiacomi TRE-03-NB, they are at good price and much better than unbranded crap.

BTW That pliers are visually similiar to Hakko pliers https://www.hakko.com/english/products/hakko_cuttingtool.html but I've not tried that ones.

10

General Technical Chat / Re: Does the electrical grid acompany network lines?

« Last post by tom66 on Today at 10:39:12 am »

What makes you think power companies modulate power lines at all with high speed data?  There are some installations in the UK that used to put high frequency carriers on mains electricity feeds to switch over timeswitched meters, and street lights, but most of those installs have gone away because besides very low data rate stuff it isn't practical (it's essentially just 'turn on now' and 'turn off now').   Nowadays RF stuff is used, like smart meters or LoRaWAN.  Powerline ethernet kit might go from one house to another if they are on the same phase, but it won't make it up the street, because the attenuation of the cable is too great at high frequencies, and there's too much interference to reliably send data.