Recent Posts

1

Beginners / Re: Analog Multiplexer-Demultiplexer Switch Vs Input Voltage

« Last post by tggzzz on Today at 11:02:45 pm »

That nexperia datasheet is poor: the PSU pins are inconsistenly labelled. TI's datasheet is at least consistent.

I suspect you are missing the key point: there are logic level translators inside the device.

The logic select controls are defined by Vih and vary with different Vcc voltage.

The analogue inputs can be between Vcc and Vee. Possible values are Vcc=+5V and Vee=-5V, but others within the limits stated are possible, e.g. Vee=0V

2

FPGA / Re: If Lattice iCE40UltraPlus has DDR primitives like ODDR in Xilinx?

« Last post by jbb on Today at 11:01:52 pm »

Or option 3: just use the SPI in Single Data Rate (SDR) mode. If that’s fast enough…

3

Buy/Sell/Wanted / Re: WTB - AU : Empty component reels in 12, 16 and 24mm

« Last post by deanclaxton on Today at 11:01:39 pm »

Element14 sell 8mm reels, plus the leader tapes. I've put feelers out on alibaba for some 12, 16, 24mm reels plus I've contacted Mid America taping and reeling to see if they will ship to AU (https://matr.com/)

4

Projects, Designs, and Technical Stuff / PC74hct4046ap Replacement

« Last post by dj_holmes on Today at 10:56:13 pm »

Hi,

first I'm way over my expertise when it comes to this. I've read a few posts from here and I knew the clever members have a much better understand that I ever will and I would appreciate some advice.

I have this Digital to analogue converter with this Philips PC74hct4046ap, everyone says its rubbish and even one member talked about modern equivelants. I'm looking for less jitter or something to tray to reduce it as its directly affecting the sound quality. I've attached a schematic of where it goes.

Thank you in advance

5

General Technical Chat / Re: A serious (as in not troll) requestfor help w/ultrasonic transducer

« Last post by watchmaker on Today at 10:55:25 pm »

i will look him up.

The workers who made parts were not considered craftsmen.  They worked in their homes and in the UK and in that period interior lighting was highly dependent on the sun, and daylight hours are more limited than in most of the USA.  This fact even draws into question many battle accounts, especially in Scotland which is even further north.

A lot of work (such as making fusee chains; 1/100th scale bicycle chains) was poor house work.

In chronometers, a "maker" such as Mercer would make the rounds and collect screws, detents, pinions, jewels wetc from people who had no idea what the parts they made were to be used in.  Then the parts would be assembled and finished into a working chronometer.  The "art" was all in the balance assembly and balance spring.  It could take a year before it was ready for trials at Kew.

Early on, jewel making was a national secret.  I think it held for 25 years or so.

6

Repair / Re: JBC SL-2300

« Last post by fzabkar on Today at 10:54:40 pm »

According to the exploded diagram on page 12 of the user manual, it would appear that this station has no stepdown transformer. Therefore, the heating element must be controlled via a TRIAC. I would think that you would need to measure the heater voltage with an RMS voltmeter.

Page 13 identifies the part numbers of the individual components of the handpiece.

https://www.jbctools.com/pdf/manual_SL2300.pdf

7

Projects, Designs, and Technical Stuff / Re: Rigol DHO804 Stand alone remoting application

« Last post by moffy on Today at 10:54:08 pm »

Thanks for the application.

8

Projects, Designs, and Technical Stuff / Re: Arduino Stand Alone Programmer

« Last post by PCB.Wiz on Today at 10:52:43 pm »

I have been looking to see if it's possible to program Arduino boards without the use of a computer. Just wondered if anyone has tried that or if it is just not feasible

MCU vendors do offer off-line programmers.
STC and Nuvoton are two examples, and these typically have Serial Flash that is loaded with your binary, and then a PGM button can update MCUs without 
needing PC connections.
Field use and production line programming are common uses.

If your code is only small (uses < 75% of the ardunio), you could use any ardunio to copy a block of its own memory to a programming port.
If you want to pgm 100% of code area, you will need some external flash/eprom/etc memory to copy from.

9

Beginners / Re: Convert US standard 115V to International 230V

« Last post by IanB on Today at 10:42:07 pm »

I'm afraid that such approach is not acceptable for safety critical devices development because it don't guarantee that device will never consume more power under some specific conditions.

Undefined/unspecified behavior of device is not acceptable because it is unpredictable and can make harm to the patient. This is uncontrolled potentially life threatening risks for the patient and it's presence shows serious issue in validation/verification process and broken quality management system. 

The above two statements are in contradiction with each other. Either you can specify the designed behavior, or you cannot. If you specify the behavior, then you cannot also say, "but this is unacceptable, because it may behave in ways other than those specified".

10

Manufacturing & Assembly / Re: Vacuum Pick-Up Tool for Rework (Includes video of my own design)

« Last post by Doctorandus_P on Today at 10:34:39 pm »

Has anyone come across any decent pick-up tool for components?

Use the magic words "luer lock". This is the fitting used between needles and syringes. It's very popular in hospitals, but also used for dispensing solder paste, glues, and all sorts of other liquids. You can buy both straight or bent needles for very little money, and the rest can easily be made from parts lying around. (Except for the vacuum pump).