Top new questions this week:

Is it better to route a pad to a trace, or a trace through a pad?

When routing a PCB, is it better to route a trace through a pad as in 1 below, or to route a pad to a trace as shown in 2 below?

pcb pcb-design pcb-fabrication

asked by Nate 20 votes answered by Blup1980 13 votes

Capacitance between Earth and Moon

Is there a capacitance between the Earth and the Moon, and if there was enough potential difference, could a discharge strike occur?

capacitance

asked by skyler 17 votes answered by LvW 11 votes

Is there a logic gate which directly outputs (A'B)' (complement of, A complement product B)?

I know I can do this with two separate NAND gates, but it would be more space consuming. Is there a single standard logic gate (e.g.; 74V1Gxxx - SOT-23 package is preferred) which produces this …

digital-logic

asked by hkBattousai 11 votes answered by Spehro Pefhany 14 votes

How can I construct my own capacitor?

I want to construct my own capacitor, primarily as an experiment in different plate configurations and orientations, so I can better understand field theory. (In other words, I'm playing, and not …

capacitor

asked by Stephen Collings 11 votes answered by Dave Tweed 12 votes

Do constant current batteries exist?

Do constant current batteries exist? If not, why not? Else, why are they not very common in the market? I am not talking about an ideal current source. But it should be a constant current source for …

batteries current-source

asked by nidhin 10 votes answered by Spehro Pefhany 10 votes

Make a custom plastic case

I have worked on many electronic DIY projects like MIDIbox (http://www.ucapps.de/), it always was fun and working but at the end, the problem was that I ended with a cool gear, but in a poor casing, …

design cases midi physical-design

asked by Basj 10 votes answered by Samuel 6 votes

Resistance, and learning for beginners

I am building an electrified "fence" of sorts to keep slugs out of my raised garden beds. The "fence" consists of two 18ga galvanized steel wires, stapled to wood and connected to a 9V battery. The …

circuit resistance

asked by Tyler V. 7 votes answered by Spehro Pefhany 6 votes

Greatest hits from previous weeks:

What is the purpose of carbon brushes in an electric motor

I just took apart our washing machine to replace the carbon brushes. Was wondering why the machine stopped working when the brushes were worn down? Also if the engine makes a wuring noise after you …

motor

asked by Shiraz Bhaiji 6 votes answered by Majenko 8 votes

USART, UART, RS232, USB, SPI, I2C, TTL, etc. what are all of these and how do they relate to each other?

As a novice electronics hobbyist, I have heard these terms and more being thrown around everywhere. At its root, I understand that they are all based on communication between devices, computers, …

communication

asked by capcom 33 votes answered by stevenvh 52 votes

Can you answer these?

RSSI-Distance calculation help

Using this question as a guide I've been trying to calculate some distances based on RSSI values that I see in our lab. I filled in all the variables with actual data or approximations where necessary …

wireless wifi

asked by thanby 2 votes

I need to create a planar inductor with a specific value of 28 nH on a 4-layer PCB. How do I determine the proper trace geometry?

I am using a Linear Technologies LT-1534 part an need to create a planar PCB surface inductor with the specific value of 28nH; i.e., the inductor will be a copper trace on the PC boards Top Surface to …

pcb components inductor copper

asked by user43595 3 votes

Sprague Vitamin Q capacitor?

We recently purchased the estate of a 94-year-old gentleman who was an electronic genius. He started building radios when he was 14 and was a ham operator and repairman of all types of electronics …

capacitor

asked by user43512 2 votes