Recent Posts

Pages: [1] 2 3 4 5 6 ... 10 Next
1
Test Equipment / Re: Unlocking Siglent SDS1104X-E, step by step
« Last post by tjohejsanhopp on Today at 05:42:58 pm »
The codes generated by the python-script seem to activate the 200MHz correctly, but no other features show up as activated, and instead stay as Trial with a countdown.
I tried to enter all codes at once, then do the reboot.
Then tried one and one, rebooting in between, same result.
Is the script not able to correctly generate the other codes correctly or am I doing it wrong?
2
Now that I think about it, I remember that FETs have a quadratic dependency of I_D vs V_GS when in saturation. So maybe you could add the threshold voltage to the input voltage, feed it to the gate, and get a quadratic current dependency at the output which you can then trivially turn into a voltage.
3
Beginners / Re: TL081 weird glitch
« Last post by sheisthedarkness on Today at 05:42:01 pm »
What kind of load is this opamp driving and what are the supply voltages?
Input is 1kHz about 2V pk-pk, supply voltages are + and -12V. I don't really need to get it working, I'm going to buy some real ones from digikey, I was just curious about your post.
4
Security / Re: Pwn the ESP32 Forever
« Last post by artag on Today at 05:37:47 pm »
@janoc  : all true, but that doesn't make me wrong.

Neanderthals were still neanderthals even when in the majority. They got out-evolved. Similarly, relying on locked up firmware to protect your IP when you ship kit that contains it (ie physical access) is doomed to failure. It's an obsolete business model.


5
Test Equipment / Re: Spectrum analyzers and Ebay
« Last post by DaJMasta on Today at 05:36:40 pm »
There's some nonsense, there's some reflection of the unit's original cost, and there's some reflection of the relative rarity/desirability of them.

It's going to be hard to find a working, tested SA for that cheap.... $1000 is a reasonable ballpark, but especially older models can be found to around $500 in good condition from some makers.  A lot of the offerings on the used market are higher bandwidth than the Rigol/Siglent units you're talking about... and their base price is on the high end of that estimate, especially if you want a TG.

Honestly, though, the Rigol SAs were some of the earlier inexpensive SAs available on the market, and they were launched at a fairly disruptive price point, so the whole point of their price point was to be a capable alternative to the used market and a new-low entry level to the new market.  Siglent, to a lesser extent Rhode & Schwarz, and some other manufacturers are trying to take a shot at this new lower priced RF gear market segment.  To some extent, it has actually pushed the prices of the used market down a bit, but there isn't anything that cheap with wide input bandwidth (which is becoming more and more important with 5G and EMI checking high frequency devices), there's plenty of bias against Chinese made equipment still around, and there are some options/performance characteristics that the new options haven't yet offered (though usually not that close to the $1000 price point on the used market).


There's a used SA buyer's guide thread floating around that could give you some ideas of brands to look at/units to consider that are less expensive.  Also keep in mind that there are sellers on ebay that will list at a price because it once cost a lot or because someone else did and there wasn't anyone undercutting the market when they listed.... so there is plenty of gear that is inflated 5-10x a price that someone would actually buy it at.
6
Beginners / Re: TL081 weird glitch
« Last post by magic on Today at 05:36:12 pm »
It's RC4558 topology, another cheap classic opamp and more suited for audio. But I admit that in the case of fake 5532 I'm not entirely sure if it's an off the shelf die because it's just so tiny. I don't know if it meets the power dissipation specs of a real 4558 and for how long >:D Though on the second thought, some discrete transistors are even smaller, so who knows, perhaps it is a legit 4558 rather than a custom job.

But you are right, going for custom tiny underpowered and oversimplified designs will probably be the final step required to break the magic 10 cent barrier ;D

Just tried, no luck, same thing. How could this help exactly ?
By biasing the output in class A. But the current conducted by the resistor at all time needs to be higher than the output current of the entire circuit. What kind of load is this opamp driving and what are the supply voltages?
8
Beginners / Re: TL081 weird glitch
« Last post by sheisthedarkness on Today at 05:34:16 pm »
Try to wire a few kohm resistor from opamp's output against Vcc. It could be the glitch disappears..
Just tried, no luck, same thing. How could this help exactly ?
9
Hola @Soldar : That is odd. With your fixed IP configuration I might suspect the HW device is the trouble. On the HW device, is the TCP/IP set to 'static address' or 'obtain address from gateway/dhcp'?
10
General Chat / 2020 Moto RAZR
« Last post by Homer J Simpson on Today at 05:33:22 pm »


Anyone checked out the new RAZR ?




Pages: [1] 2 3 4 5 6 ... 10 Next