All Questions
0
votes
0answers
8 views
Giant Capacitor in Power Supply Blew. Possible Cause? - Dell XPS 8700 [on hold]
The giant capacitor in the middle of my Dell done gone blew up.
As far as I know, capacitors blow from extended stress. Is that true?
What is the function of this particular capacitor (its ...
0
votes
0answers
6 views
Using a fruit or salt-water battery to power a motor
I´m trying to build a fruit or saltwater battery to power a motor.
From my 8 cell saltwater battery connected in series, I get a reading of 5V or so and 2-3A... but it won´t fire up my 5V DC motor. ...
0
votes
1answer
11 views
FCC Low Oscilation
I have heard that if a circuit is operating at less then 1.2 MHz it does not need FCC certification.
Does an ATMega328 with with a 1Mhz External crystal, and the internal clock not used qualify for ...
0
votes
0answers
10 views
preventing Cell Phone from interfering with car cassette adapter
My old car has a cassette player and I use an adapter for my MP3 player. I was hearing strange interference occasionally and finally figured out that my cell phone causes that when a call or message ...
1
vote
3answers
35 views
Hot and neutral have similar voltage to ground - finding the problem
I have an APC battery backup and surge protector for my computer. It has a light, labeled "Building wiring fault." This light is on, and my computer will not start. I am unemployed and my landlord is ...
0
votes
2answers
23 views
What to do about two logic gates connected to the same wire?
If I have two logic gates (made of mosfets) with outputs connected to the same wire or bus, I encounter an issue where, when the logic gates are at opposite logic levels they are both trying to drive ...
2
votes
0answers
25 views
Would this Li+ flashlight circuit be considered safe?
I recently got an inexpensive (~$4 USD) Li+ 18650-powered flashlight from banggood.com, one of my favorite sources for inexpensive Chinese electronics to tear down and hack for fun :)
I wanted to ...
1
vote
1answer
10 views
Turn on 12v car amplifier with ATX POWER_GOOD?
Does anyone know how to turn on a 12v subwoofer amplifier, using the ATX power supply control wire for POWER_GOOD?
I am using an Azza model PSAZ-1000A14S, 1000 watt, single 12v rail, computer power ...
1
vote
0answers
14 views
Remove the load of buck converter
I have a buck converter that is delivering 6A to a load of 3ohm load.
I'm measuring the output current and stop increasing the dutty cicle when the current reach 6A, at this moment the output voltage ...
-2
votes
0answers
14 views
Non-classical / Alternative Logic Systems
I have simple, straight forward question:
What are other logic system (or concepts) other than binary (boolean's) ?
In your answer include the name of a logical model (obviously), how it works and ...
1
vote
2answers
17 views
Metastability error propagation with flip flop
I do have a confusion regarding the metastability resolution using flip flops , I know that I should add synchronizer of two or three d-flip flop to guarantee a safe transmission at clock domain ...
2
votes
2answers
35 views
How does the maximum transmission rate depend on the carrier frequency?
This question refers to the following excerpt from Computer Networks by Andrew Tanenbaum:
The amount of information that an electromagnetic wave can carry is related to its bandwidth. With current ...
0
votes
0answers
14 views
Calibre LVS error
Hi i did my layout in cadence virtuoso and i had passed clean the DRC and LVS. Now when i run calibre DRC i am getting "metal density error". I was testing a layout design that was already fabricated ...
0
votes
1answer
30 views
Why is the conducting layer in resistive touchscreen placed perpendicularly?
I just learned that in analog resistive touchscreen, conducting layers (usually made of indium tin oxide) is placed perpendicular to each other. One on the top flexible film, and one on the bottom, ...
4
votes
3answers
277 views
How do electricians know where the line is down?
I had a power outage and I thought about the utility poles near the street. How do electricians know which power line is down considering that there are many miles of them? For example, if there's a ...
-3
votes
0answers
27 views
Checking voltage levels? [on hold]
Whats the simplest way to check voltage levels? say I have a 1.5V power rail, I want to check that the power supply is providing 1.5V, if its not, do something predefined.
0
votes
1answer
26 views
DIY Remote Control Circuit [on hold]
I am trying to make a simple remote control arm and car, and I have all the parts for the arm and car but the problem is making the remote control part. I am new to Remote Controls and don't know what ...
0
votes
2answers
49 views
Will this P channel Mosfet switch work from a 3v3 GPIO
I'm designing a circuit that I can reuse over again to switch loads of different kinds from around 8-30v and from around 0.5-15amp. Like a universal Solid state relay but I want my own custom circuit ...
0
votes
0answers
8 views
Circuit problems for pressure transducer
I am working on a circuit to amplify my output voltage from a pressure transducer with the range of events 3-20 mV to be ready by a national instrumentation DAQ USB 6008
I have worked on 2 circuits ...
0
votes
2answers
22 views
Door lock relay needs higher amperage - what relay to use?
I have a door lock that requires 12VDC 750mA to get it to unlock, then it drops to 350mA to keep it open. My door controller has a max load of 500mA, so it won't work connected directly to the door ...
0
votes
1answer
26 views
Extrinsic semiconductors: why can't electrons/holes in the band gap conduct?
Normally, no electron energy states exist in the band gap, the gap between the valence band and conduction band in a semiconductor.
However, if we dope the semiconductor, i.e. add donor (n type) or ...
1
vote
2answers
60 views
How to build a “stable” voltage divider?
I'm trying to build a EMG (electromyography) acquisition circuit. In order to power the operational amplifiers I'm using a voltage divider with 6.2k resistances and the voltage from the wall is 18V. ...
-3
votes
0answers
25 views
USB Oscilloscope design(receiving data on PC, stm32 usb library) [on hold]
This is going to be rather huge question, so I will provide bounty (in 2 days) if I don't get good answer(or give bounty to good extensive answer if answered early).
So I am trying to build some kind ...
0
votes
1answer
44 views
Does the physical distance from electrolyc capacitor to inductor matter?
I am designing simple LC circuit (L=470uH, C=1000uF) for 12V / 12A (1 Ohm load):
As you can see, I did do some soldering already (without too much or noob thinking). The capacitor and inductor ...
0
votes
1answer
25 views
How exactly is the location of contact determined on an analog resistive touchscreen?
I am doing a physics project for my high school course. My project is to explain how a resistive touchscreen works.I have no engineering knowledge.
From a description I found on computerworld.com ...
0
votes
0answers
12 views
Heatsink for diode and mosfet in 12V 15A LC circuit
I am trying to design simple step down bulk voltage converter:
This circuit will be 'stepping down' 12V to lower voltages depending on needs (driven by 20kHz PWM with variable duty cycles). The ...
0
votes
0answers
10 views
DC bushless motor position tracking in gimbals
I see that gimbal motors often are DC brushless, like this one. However, how is position tracking done? There doesn't seem to be sensors integrated and they only have 3 wires (3 phase?). Position ...
1
vote
0answers
16 views
driving a Peltier with a MOSFET
I am attempting to drive a Peltier device using a single MOSFET, controlled by a microcontroller.
I am working with several different peltiers and various MOSFETs, so wont provide component details ...
0
votes
3answers
33 views
Can I power this device with a USB port? [on hold]
I have an audio looping device known as the TC Electronic; Ditto Looper. It has its own dedicated AC/DC power adapter but I was wondering if I could possibly build a cable capable of powering it with ...
0
votes
0answers
24 views
Electromagnetic brake
I would like use an electromagnetic brake on low rpm motor(2-5 rpm) to apply a specific reverse couple(10Nm).
Most of electromagnetic brakes I seen, have a working range of 40-3000 rpm but I dont want ...
0
votes
1answer
12 views
How to calculate the transmission ( channel ) bandwidth in a digital communications system?
Is it the bandwidth ( BW ) of the individual pulse or should I generate a random process and calculate the BW from its PSD.
In my class we considered it the bandwidth of the raised cosine when we were ...
0
votes
0answers
6 views
My rca 7 voyager (RCT6773W22) tablet won't work [on hold]
I tried everything like holding power and volume + , charging , holding power, taking out case, Nothing works please help me
3
votes
1answer
351 views
Can some body help me understand some parts of a schematic circuit?
I have circuit schematic, and I do not understand what are the parts in red circles and what do they do.
The schematics are from a movement sensor using a PIC micro controller, infrared LED and an ...
-1
votes
2answers
51 views
'V' groove routing at cheap PCB manufacturers
I am designing some PCBs, which I intend to prototype, and then get small volumes produced for personal use at a cheap PCB house such as Itead, DirtyPCBs, or Seeedstudio Fusion PCB. These board houses ...
0
votes
2answers
76 views
Why would phones have a radio receiver, but not activate it?
According to some recent news articles, many cell phones including iPhones and Androids have built in FM receivers, but they are not "activated". Why would the phones have such a feature but not ...
0
votes
0answers
31 views
What is this 5 terminal part marked AA17s?
I am doing some reverse engineering with a toy RC helicopter pcb, trying to make my own.
At the original pcb there is a small 5 terminal part marked with "AA17s" on top, which I have no idea what it ...
1
vote
2answers
44 views
Difference on component size (Resistor, Capacitor, inductor)?
I am wondering if there is any difference (a part the size) between two SMD components who have same characteristics but different size, example:
RESISTOR, THICK FILM, 100k, -5%/+5%, 0.063W, 50V, ...
0
votes
0answers
35 views
Is a shunt regulator recommended in this helicopter design?
I am doing some reverse engineering with a toy RC helicopter pcb, trying to make my own.
(Actual question at the end)
This pcb (both the original and my own) has to drive 4 small dc motors which in ...
0
votes
2answers
27 views
Alternative to using the LM272 for driving a DC motor
In this instructable, the LM 272 is being used for driving a simple dc motor. My friends and I are trying to use the same concept for our project(which is similar in nature), however there are only ...
0
votes
2answers
45 views
Micro/standard servo resolution
I am building a project which requires a very fine servo resolution (<=.1 degree). I understand there is a lot that goes into servo resolution like digital v analog, dead-band, # of poles, ...
1
vote
1answer
26 views
Can I use barrier rectifier as a diode in bulk converter circuit?
I have this LC circuit which will work under 12V and quite high load (10-20A):
The diode D1 must be a shottky diode but the only similar thing I have at the moment is actually 3-leg MBR3045CT ...
1
vote
1answer
16 views
Solar cell charging and battery chemistry for low power 2.4-3V supply?
I've recently been looking into the possibility of using an amorphous silicon solar cell (like they have in calculators) to supplement my very low power BLE system's current consumption to extend the ...
3
votes
1answer
41 views
Should I use MLCC or Tantalum capacitors near the board's power input?
My board consists of a microcontroller, some RF modules (i.e. bluetooth, wifi, etc), and a few other gadgets.
It is powered by a 12V barrel adapter. I've read conflicting reports whether it's best ...
0
votes
3answers
43 views
Voltage proportional comparison (division?)
I'm looking for a circuit that produces an output voltage which represents the voltage between A-B compared to B-C here. IE if AB is 10V and BC is 1V, the output is 10V, and if AB is 10V and BC is 2V ...
0
votes
0answers
6 views
cc2640 OAD configuration
I'm working in my application with the CC2640. I have read that I need the CC2540 dongle usb for OAD. I have available two CC2640, is it possible to do the OAD for the CC2640 from another CC2640? or ...
3
votes
2answers
38 views
Parallel input to serial output
I have been learning a bit about electronics. In particular I have been playing with the shift register 74HC595. Here I understand how bits are moved into the register serially, that is one bit at the ...
0
votes
1answer
30 views
Building a USB Charging Circuit Using 120VAC
first time here. I've been working on developing a 3-port USB charging circuit coming out of a 120VAC wall outlet. Here is a basic schematic of what I'm following.
I've been having some trouble ...
1
vote
2answers
44 views
Amplifiers: Periodic and non-periodic signals
All the signal amplifiers (op amps) I've dealt with thus far use periodic signals. The idea of bandwidth is natural when dealing with these periodic signals because it is just a description of the ...
-4
votes
1answer
62 views
What kind of a Switch is this? How can i use this Switch
I found this switch in DVD drive, I think its a kind of mechanism which reverses the polarity of the motor. If so How can I use this with arduino uno? THis link might be useful : ...
0
votes
0answers
16 views
No hotspot in a component created in Altium
I have added a component to an SCH library in Altium.
I have just drawn the component (just the schematic and not the footprint!) and added to it a model that I found on the TI website. I just need ...
