Recent Posts

1

General Technical Chat / Know of any good books/sources of useful electronic schematics?

« Last post by ballsystemlord on Today at 02:20:01 am »

Hello,
When looking up how people make this or that, I can't help but find that many of the schematics offered online are either not functional or poorly designed. It's not just me either. Some YT-ers make videos about fixing bad circuit designs you can find online.

Towards the end of getting a set of good/workable circuit schematics, I searched for books on the subject. I found some, but they're all from the late 1960s though the 1970s. This means that a lot of things can/have been converted into ICs or improved through the use of alternate tech, such as IGBTs/MOSFETs. So such books are a bit dated.

Do you know of good books or resources for circuit schematics?

Thanks!

2

Buy/Sell/Wanted / Element 14 Australia Fire Sale

« Last post by EEVblog on Today at 02:19:47 am »

Up to 99% off AU warehouse sale, the spreadsheet is vast:
https://au.element14.com/fire-sale?ICID=I-HP-LB-FIRE-SALE-MAR24-WF3616377

3

Power/Renewable Energy/EV's / Re: Flyback controller output voltage and amps under load

« Last post by xavier60 on Today at 02:10:22 am »

Post the schematic. At what load current does the voltage begin to decrease? Or is it at all loads?

4

Microcontrollers / Re: Can't disable alarms on DS3231 RTC module

« Last post by Peabody on Today at 02:08:33 am »

Ok, I did a test writing the value 97 into register 7, which is the seconds register of Alarm1.  97 is 0b01100001, which is 61 in binary coded decimal.  Then I read back the value in register 7 once a second to see if it changed.  In more than a minute, it did not.  I also read back the status register to see if the alarm flags were ever set.  They were not.  So it seems you can write an invalid number into an alarm register, and it will not be error-checked or changed.  So since the actual time will never contain such an invalid number, no match will ever occur, and the alarm flags will never be set.

To do this test, I had to clear the A1M1 bit in register 7, and set the A1M2 - A1M4 bits in registers 8, 9 and 0xA.  If A1M1 is also set, it will match every second no matter what value is in register 7.

5

Power/Renewable Energy/EV's / Re: Flyback controller output voltage and amps under load

« Last post by thomasx on Today at 02:05:47 am »

Ok, so basically in both DCM and CCM the current can go higher. In this case the converter transits from DCM to CCM at about 40W load  (if I remember correctly).

My biggest concern however, is the drop in voltage. This is supposed to be an 84W power supply, 12 V x 7 A, but the highest output I can reach is 57W at about 8 amps 7 volts, which is totally off the chart in all ways.

6

Microcontrollers / Re: It Came from Mainland China: Bootleg MCS-251 "32-Bit 8051"

« Last post by PCB.Wiz on Today at 01:57:08 am »

AFAIK, the STC32 parts currently have only single tool chain support - needing Keil C251 to code.

I've been more tracking their sibling parts, the STC8H family, which use standard 8051 tools.

https://www.stcai.com/cp_stc8hxl

eg the STC8H8K64U part is their first with hard-coded USB, and comes down to SO16 in size.

It's a challenge keeping up with the details, as they seem to upgrade things with every sub-family spin.

Thus the newer STC8H2K8U (STC8H2K12U, STC8H2K17U) has better PWM than the parent STC8H8K64U, and the very new STC8H2K32U (STC8H2K24U,STC8H2K16U), has an improved 32b ALU block,

https://www.stcaimcu.com/forum.php?mod=viewthread&tid=5721

mentions  STC8H32K64U

7

EEVblog Specific / Re: EEVblog #978 - Keysight 1000X Hacking

« Last post by Anthocyanina on Today at 01:56:01 am »

Just wanted to share that I was successful obtaining a previous backup of my scope from the seller. Whew, a learning event.  Let’s see if I can keep my goof-ups to a minimum from this point forward!   

Lee

great! do you know if it was FERCSA's firmware? or another custom one?

8

Microcontrollers / Re: It Came from Mainland China: Bootleg MCS-251 "32-Bit 8051"

« Last post by amyk on Today at 01:48:14 am »

STC have been making 8051s for a long time, so that's not surprising, but they also have an ARM-based series that starts with STC32F. There's also stuff like this from other companies: https://www.eevblog.com/forum/microcontrollers/whats-this-8051-clone/ Chinese MCU market is really weird.

9

General Technical Chat / Re: Powering an LED from international line voltage

« Last post by NiHaoMike on Today at 01:43:53 am »

How about use multiple smaller LEDs in series? Then you'll need less current for the same brightness, possibly to the point where a series resistor would become practical.

10

Beginners / Re: 5V buck converter debugging

« Last post by davegravy on Today at 01:42:50 am »

I would suggest trying again. Bring it up to 4 volts and check some waveforms, I am hopeful with that information you will find the issue and be up and running 

I don't have a great scope but these were all taken with my 10X probe. Does this suggest there's insufficient input filtering?

Vin at 3.6V RMS


Vin at 3.7V RMS (where the IC starts drawing current)


SW1/2/3 (Vin=3.7V RMS)


Vout (Vin=3.7V RMS)


Cboot (Vin=3.7V RMS)


SW4 (Vin=3.7V RMS)