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1500 questions
24
votes
6 answers
Writable area on a PCB
I would like to create an area on my PCB where you can write on with a pen.
Is this possible, and if so how should I do it?
Tim Jager
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24
votes
6 answers
In earlier tape recorders, how was tape spool angular velocity adjusted?
Tape recorders that use spools of magnetic tape transfer the tape from one spool to another as the tape plays/records. The spool with less tape must be rotated faster than the other. Here is such a tape recorder/player. This is the Craig Model…
quantum231
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24
votes
2 answers
Via fences for noise reduction of a chip antenna?
I'm working on a 4-layer PCB that has a wifi module and a chip antenna, the antenna is placed at the corner of the PCB and the copper beneath it is removed, I see that via fences are used on the breakout board of the same module, but the reference…
mux
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24
votes
0 answers
Switch from JTAG to SWD with bitbang sequence on STM32F103VB
I am trying to switch from JTAG to SWD without any external devices. Why? Because I would like to use the SWO pin to send a stream of logging information to
another device.
To accomplish this without using an external debugger, I have connected the…
Heneer
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24
votes
5 answers
How could have Banksy kept an RF receiver running for 12 years?
I'm talking about Banksy's "Girl with balloon" painting that shredded itself at auction.
I think the general consensus is that he didn't, and that it was set up before the auction (or a couple years ago, not 12 years). But lets say he did, how could…
Daffy
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24
votes
4 answers
Is it advisable to stay stick to Arduino IDE?
Is it better to move to AVR studio (or any other better alternative?) over the Arduino IDE. Feel like it's so simple and childish. I need to know the experts idea and choice..
Anubis
- 1,490
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24
votes
5 answers
Cleaning Circuits with Compressed Air
I've been arguing with a colleague whether it is a sensible solution to clean dusty PCBs with compressed air. While I think this is the best solution (nothing touches the PCB), he claimed that spraying off the dust can cause ESD, because the charges…
Count Zero
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24
votes
8 answers
What is a 50-ohm antenna? How would you make one?
This is an intentionally very open ended question. What does it mean for an antenna to be a 50-ohm antenna at some frequency? How do you make a 50-ohm antenna for say 433.92MHz? What are the options? What are the consequences of it being different…
vicatcu
- 22,695
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24
votes
4 answers
Do you need high voltage or current to produce a spark?
An electric spark can be formed when there is high potential energy between two conductors, right? My question is can a spark be formed with high current and low voltage or only vice-versa?
JingleBells
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24
votes
3 answers
74LS vs. 74HC series ICs for Ben Eater's 8-bit Computer
What are the primary differences between 74LS series and 74HC series ICs? I know that LS series are TTL and HC are CMOS, but beyond that what are the key differences?
For example, Ben Eater uses LS series chips in his 8-bit computer. Why would he do…
rjm27trekkie
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24
votes
3 answers
Should I isolate grounds of an isolated DC/DC converter?
If I use an isolated DC/DC converter, when designing the PCB, should I isolate the ground of the input and the ground of the output as shown below?
I've never isolated grounds (except for AGND and DGND) but always used one single ground plane for…
Abdella
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24
votes
8 answers
Communication between multiple microcontrollers
I'd like to start implementing a system consisting of N microcontrollers (N >= 2 MCUs), but I would like to know the possibilities to let them communicate one with the other.
Ideally, (N-1) microcontrollers are placed inside the house acting as…
user51166
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24
votes
3 answers
Why are chip designers called "triangle pushers"?
I heard chip designers being described as "triangle pushers," the idea being that somehow the logic on the chip was formulated by arranging triangles on the silicon in certain ways. How does this work? I don't understand how triangles can be…
Tyler Durden
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24
votes
2 answers
Review request: DIY DC to 50MHz differential oscilloscope probe
Given the cost of proper differential probes, i've decided to make my own. The requirements are:
DC to 50 MHz 3db bandwidth
A few selectable input voltage ranges, from 3V pk-pk to 300 V pk-pk
Better than 1/500 common mode rejection ratio
A…
jms
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24
votes
2 answers
Alternatives to SPI because of EMI
I currently make a system consisting of a plastic enclosure which contains an MCU talking to 7 ADCs using 2MHz SPI over wires about 5cm long.
The problem is that I'm concerned about EMI. Everything I have read suggests that any kind of digital…
Rocketmagnet
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