Engineering and technology notes

Philo Farnsworth

Jovan Stosic March 12, 2022

Philo Taylor Farnsworth (August 19, 1906 – March 11, 1971) was an American inventor and television pioneer.He made many crucial contributions to the early development of all-electronic television. He is best known for his 1927 invention of the first fully functional all-electronic image pickup device (video camera tube), the image dissector, as well as the first fully functional and complete all-electronic television system. Farnsworth developed a television system complete with receiver and camera—which he produced commercially through the Farnsworth Television and Radio Corporation from 1938 to 1951, in Fort Wayne, Indiana.[7][8]

In later life, Farnsworth invented a small nuclear fusion device, the Farnsworth–Hirsch fusor, employing inertial electrostatic confinement (IEC). Like all fusion devices, it was not a practical device for generating nuclear power, although it provides a viable source of neutrons.[9] The design of this device has been the inspiration for other fusion approaches, including the Polywell reactor concept. Farnsworth held 300 patents, mostly in radio and television.

Source: Philo Farnsworth – Wikipedia

Forum – EasyEDA – An Easier Electronic Circuit Design Experience – EasyEDA

Jovan Stosic February 18, 2022

Change the design rule, not your vias!. Just go into your Design Rule… settings and lower the via diameter and drill sizes by a fraction (for example, .6mm and .304mm) such that they are slightly smaller than whatever you already placed on your board. Your vias will then nicely exceed the minimum and all the errors will go away.

 

Source: Forum – EasyEDA – An Easier Electronic Circuit Design Experience – EasyEDA

Forum – EasyEDA – An Easier Electronic Circuit Design Experience – EasyEDA

Jovan Stosic February 17, 2022

The quick way:

  1. Before you start your design, go to:

https://easyeda.com/order

  1. Click on the question mark next to “Layers”;
  2. Read the page that opens;
  3. Select 4 or 6 layers;
  4. Click on the question mark next to “Impedance”;
  5. Read the page that opens;
  6. Select “Yes”;
  7. Click on “Impadance calculator”;
  8. Choose your desired transmission line structure (single ended or differential covered microstrip, inner layer stripline, offset stripline);
  9. use the calculator and note the trace dimensions.
  10. Following the Design Flow in the Tutorial, start your design in the Schematic Editor of EasyEDA and then convert it to a PCB, then manually route your layout using the calculated trace dimensions.

The longer way for 4 and 6 layer PCBs only:

  1. Before you start your design, read “Controlled Impedance PCB” in:

https://jlcpcb.com/capabilities/Capabilities;

  1. Choose your PCB stack up:

https://jlcpcb.com/quote/pcbOrderFaq/PCB%20Stackup

or:

https://jlcpcb.com/client/index.html#/impedance;

  1. Choose your desired transmission line structure (single ended or differential covered microstrip, inner layer stripline, offset stripline);
  2. then use:

https://jlcpcb.com/client/index.html#/impedanceCalculation

  1. use the calculator and note the trace dimensions.
  2. Following the Design Flow in the Tutorial, start your design in the Schematic Editor of EasyEDA and then convert it to a PCB, then manually route your layout using the calculated trace dimensions.

The more detailed and flexible way but which will not be covered by any warranty from JLCPCB:

  1. Install a copy of a simple field solver impedance calculator:

https://www.maartenbaert.be/alterpcb/tlinesim/
https://sourceforge.net/projects/mdtlc/files/development/0_2_1_dev/
or:
https://sourceforge.net/projects/mmtl/files/tnt/1.2.2/

  1. Choose your PCB stackup:

https://jlcpcb.com/client/index.html#/impedance

  1. Then use their figures as inputs to the field solver to calculate the trace widths and spacings for your desired transmission line structure (bare microstrip, covered microstrip, buried microstrip, symmetrical stripline, offset stripline, differential variants of microstrip and striplines,coplanar wiveguide, etc. etc.)
  2. Note the trace dimensions.
  3. Following the Design Flow in the Tutorial, start your design in the Schematic Editor of EasyEDA and then convert it to a PCB, then manually route your layout using the calculated trace dimensions.
  • Note that:

(i) for 2 layer PCBs the information provided about the PCB material is incomplete;
(ii) using tools and stack ups other than those specified by JLCPCB will almost certainly void any claim against them for the resulting PCB failing to the target impedance.

 

Source: Forum – EasyEDA – An Easier Electronic Circuit Design Experience – EasyEDA

JLCPCB’s Basic vs Extended

Jovan Stosic February 11, 2022

There’s a subset of JLCPCB’s parts that they call Basic parts. All other parts they support are called Extended parts. Basic components have a cost per unit. For each type of Extended component you use, JLCPCB adds $3 to your total cost. If you aren’t careful, this can really add up. For example, if your board needs 10 different types of resistors, and you choose Extended components for these, then you’ll end up paying $30 in fees on top of your per-component and assembly costs.

I found the best way to make sure I was choosing Basic parts was to use JLCPCB’s parts page instead of trying to do it entirely through the Library. In EasyEDA’s Library pane, you can filter for JLCPCB Assembled components, and sort by the SMT Type column, but I found that this was sometimes out of sync with JLCPCB’s parts database, so you may not find parts that JLCPCB actually has, or they may tell you something is Extended when it’s actually Basic. To avoid that, just go to the JLCPCB parts page and browse or search for what you’re looking for, then filter for Basic Parts.

source: http://www.evankrall.com/posts/jlcpcb-smt/