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Top new questions this week:

ATmega8515 - odd results when auto-detecting external SRAM

I'm using an ATmega8515 microcontroller for a one-off hobby project. This chip has an external memory interface which can directly address 64 kilobytes of external SRAM. ATmega8515 datasheet. For my ...

microcontroller atmega sram  
user avatar asked by Wossname Score of 7
user avatar answered by Tom Carpenter Score of 11

Do any power loads require both power lines disconnected by the "off" switch?

The typical approach to interrupt the flow through a circuit is interrupt it at a single location as in the left image. Do any power loads require both power lines disconnected by the switch as in the ...

user avatar asked by dtech Score of 7
user avatar answered by vu2nan Score of 14

Best way to avoid vendor tie-in with DC/DC Converters

I frequently utilize DC/DC step-down converters in many of my projects. Mostly these converters have a low voltage input (Vin_max = 30Vdc) and low output current (Iout_max = 1-2A). There's a plethora ...

dc-dc-converter alternatives  
user avatar asked by Jan Riha Score of 7
user avatar answered by colintd Score of 15

Unphysical voltage in SPICE simulation

I was exploring a lumped approximation of a distributed RC network (sort of a lossy RC transmission line/ladder network). Everything made complete sense until I observed the voltage "gain", ...

remote-control lumped  
user avatar asked by lukas123321 Score of 7
user avatar answered by Tim Williams Score of 18

In English, a "'shrouded" connector is one with walls that surround its mate. What is the corresponding adjective for its mate?

For the last few years, I have been searching for an adjective that describes all connectors that fit inside a shrouded connector. I have not found a satisfactory one. I am about to go to press with a ...

connector terminology  
user avatar asked by Davide Andrea Score of 6
user avatar answered by Tom Carpenter Score of 8

LED circuit seems to defy Ohm's law. Of course it’s something else

Ok, I promise I have checked and rechecked values here. I needed to make an LED circuit for a Christmas display using one white LED inside a Santa Claus figure to replace the incandescent light bulb ...

power led  
user avatar asked by J Acker Score of 5
user avatar answered by Justme Score of 14

Identification of shiny metallic blocks on the PCB

What are these shiny metal-like components in the images below? Is that kapton tape covering for ESD protection?

pcb identification  
user avatar asked by courageouslywin Score of 5
user avatar answered by colintd Score of 5

Greatest hits from previous weeks:

Why use capacitors?

Why do you need to store the voltage for some time in a capacitor? I've always assumed circuits to work when you power it on and stop when you power it off. Why can't the whole circuit be drawn ...

user avatar asked by user1424 Score of 45
user avatar answered by pingswept Score of 48

Why does this LED bulb have an energy efficiency rating of 'F'?

In my home, I have some halogen spot lights, which have an energy efficiency rating of 'C': I would like to replace them with more efficient LED bulbs, but looking on the Philips website, they claim ...

led efficiency lighting halogen  
user avatar asked by Rocketmagnet Score of 39

What is input and output impedance of an opamp?

I have never understood input and output impedances of an op-amp. If anyone can explain what these two terms mean in an op-amp I'd highly appreciate it. Thank you! http://www.eecs.tufts.edu/~dsculley/...

operational-amplifier impedance  
user avatar asked by user734861 Score of 47
user avatar answered by Phil Frost Score of 56

Does mAh measure how long a battery would last?

I know mAh tells how much milliamperes a battery can deliver in an hour. But does that also tell how many hours the battery would last? Sorry but I don't really get it. If we're talking about a water ...

user avatar asked by supertonsky Score of 65
user avatar answered by Phil Frost Score of 82

What are the different types of solder used for?

How do I know when to use lead, flux-core, lead-free, or any other kind of solder out there? Do you have any tips on solder gauge for specific applications?

user avatar asked by cmchap Score of 92
user avatar answered by Lou Score of 57

Relationship of Induction Motor Frequencies

I would like to know how the mechanical rotor frequency [Hz] can be obtained from the electrical stator frequency [Hz]? This is no homework! I have consulted several books as well as the web but could ...

motor frequency induction-motor formula-derivation  
user avatar asked by Maxwell1919 Score of 1

How to change rotation direction of 3-phase electrical machines?

I was taught that if you want to change the direction of a three phase rotating machine that is rotating in forward direction, you interchange the phases. Since the phases has the same features (...

motor three-phase  
user avatar asked by Ezeatum Solomon Score of 2
user avatar answered by Andy aka Score of 14

Can you answer these questions?

Resistor in RC circuit

I have an RC circuit connected to a switch node as a snubber. I am facing difficulties determining the required power rating for the resistor. I have looked at this and this, however, it remains ...

power resistors  
user avatar asked by HV16 Score of 1
user avatar answered by periblepsis Score of 0

Is the relationship between impedance and three phase apparent power different in Delta and Wye?

I looked up this article https://www.electricalpereview.com/base-impedance-single-three-phase-values-equal/ and I am really confused about the final equation. The author says that this applies for ...

user avatar asked by dogdump123 Score of 1

WS2815 circuit erratic behaviour

I have been having problems driving WS2812 LEDs; the radiated emissions were too high to pass UK tests. See Radiated emissions from WS2812 LEDs I finally bit the bullet and went for LEDs on a printed ...

rgb ws2812b  
user avatar asked by srlevitt Score of 1
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