Electrical Engineering Weekly Newsletter
Electrical Engineering Weekly Newsletter

Top new questions this week:

True GPS Location - At the Antenna or Receiver Chip?

Suppose I have a GPS unit attached to an antenna through a 50 meter coax cable. How would the location as calculated by the GPS unit be affected by the cable length? As a bonus question, how would ...

antenna gps  
asked by David Gardner 19 votes
answered by Umar 21 votes

Why do characteristic impedances matter only when traces are longer than half a wavelength?

Why are characteristic impedances of traces not considered when the traces are shorter than half a wavelength? I've had the same issue with light diffraction, which happens when pinholes are smaller ...

pcb rf radio impedance  
asked by user42875 18 votes
answered by helloworld922 7 votes

Why is it so hard to find component footprints?

When designing PCB's, I find myself very often having to make footprints for a significant portion of the components on my board. This tends to be very time-consuming, as (in Altium at least), ...

pcb-design footprint  
asked by zplizzi 11 votes
answered by Techydude 13 votes

Voltage and current measurement of battery Single ended or differential?

I am trying to measure battery's current and voltage for a battery charging/monitoring project. I have read all about current sensing (including high side & low side sensing). And i have decided ...

adc differential single-ended  
asked by yiipmann 8 votes
answered by The Photon 4 votes

How to solder micro stepper motor pins?

I have a hobby project where I would like to use micro stepper motors as shown in the picture below. However, as you might be able to see, the spacing between the pins is incredibly tiny and each pin ...

soldering stepper-motor  
asked by Kolban 6 votes
answered by Mats 0 votes

Why does EM radiation travel much further than the magnetic field of an equivalent power electromagnet?

If both fall of as 1/r^2 from the source then why can radio waves travel around the world and still be picked up easily at the right frequency but the field from a powerful electromagnet can not?

rf electromagnetism wave  
asked by LostInPlace 6 votes
answered by Andy aka 1 vote

Measuring currents between 100pA to 100uA

I want to measure absortion/resorbtion currents of dielectric when applying 1000V, 1500V, 2000V. I have made a small currents measuring device using a LOG114: I use : LOG114 with 1uA reference ...

current-measurement dielectric  
asked by Nedelcu Bogdan 5 votes
answered by WhatRoughBeast 2 votes

Greatest hits from previous weeks:

Why do we connect a battery to ground when jumping a car?

This may seem like a very simple question, but I've searched all over the place and haven't found an answer. When jumping a car, we connect the + end of the charged battery to the + end of the dead ...

batteries ground automotive  
asked by Ken Levinski 5 votes
answered by Kaz 15 votes

What is a decoupling capacitor and how do I know if I need one?

What is a decoupling capacitor (or smoothing capacitor as referred to in the link below)? How do I know if I need one and if so, what size and where it needs to go? This question mentions many ...

capacitor decoupling-capacitor  
asked by Lawrence Johnston 87 votes
answered by penjuin 60 votes

Can you answer these?

Wireless communication under water

I am looking for a under water wireless communication, distance up to 3000 meters. For this I quickly did some research on it and found out that Acoustic communication would be the best solution since ...

wireless communication  
asked by Electronic Curious 5 votes

Send a file to an SD card over SPI

I am using a PIC18F4620 and an XC8 compiler. I am trying to create a file and send it to the SD card. I am using the MDD library from the MLA Legacy. My main is: FSFILE * file; char sendBuffer[22] = ...

pic spi sd fat  
asked by user2344158 1 vote

How would you dampen this little quadcopter?

Well, I made a little quad from scratch. From scratch as in from PCB design. After assembling, testing, some coding, it turns out my accelerometers get WAY TOO MUCH vibrations and I can't detect ...

accelerometer vibration quad-copter  
asked by user1906583 3 votes
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