All Questions
0
votes
0answers
4 views
How to make a solder paste more liquid-like
I recently purchased Kester EP256 solder paste. This is the first time I am working with it, and placing it on the PCB is very difficult. I do not know how viscous it should be, but it seems to be too ...
0
votes
0answers
6 views
Faulty Portable Charger
I have a portable phone charger with a capacity of 4500mAh, input of 5V and 1A, and an output of 5V and 1A. I am trying to charge my black berry curve 9320 with it but instead the portable charger ...
0
votes
1answer
28 views
How to arrange resistors for certain resistance
This question is like this one. I have two 1 ohm resistors, six 2 ohm resistors, and want 2 ohms total. All resistors must be powered (since they are actually speakers.) How do I do this? Ideally, a ...
1
vote
0answers
20 views
How to add a desirable phase shift in the input from 3-phase ac mains?
I want to build a 12 pulse rectifier circuit. I know delta-wye or wye-delta transformers can be used to add phase shifts equal to the multiples of 30, but I don't want to use transformers. Is there ...
0
votes
2answers
32 views
Switching between AC and DC input
Let's say I need to power a 9v device with an input power source that is either AC or DC and changes almost randomly. Is there any way for me to detect in a circuit when AC changes to DC or vice-versa ...
-2
votes
0answers
20 views
Power generated goes to load or energy storage? [on hold]
When we have a source of electricity, like PV for example, and we want to power up a DC load and with the excess power store energy to a battery, how can we achieve that? In what way should we connect ...
-3
votes
0answers
21 views
Control Systems Real World examples with RHP Zeros and/or Double Integrators
Can Anyone give me two separate real world control systems examples. One example system which has RHP zeros. Another examples where the system has double integrator poles. If any link can be provided ...
0
votes
3answers
47 views
Transfer Function
I have this question but I am really confuse about how to start, can you please give me some helpful hint.
Let us assume we have a DC voltage measured in a circuit, called Vin. We intend to build a ...
2
votes
3answers
48 views
Why is KCL giving me the wrong solution?
I'm trying to derive the gain of the following common base amplifier circuit:
To do this, I drew the equivalent T-model circuit: .
The problem I have is that I get two different transfer functions ...
-4
votes
1answer
47 views
How transistor convert DC to AC? [on hold]
I'm fairly new to electricity. I know that a transistor can be used to convert DC to AC, but i really don't know why. Can anyone please explain how transistor can convert DC to AC ?
1
vote
1answer
39 views
What adapter would power device that runs on 3 D batteries? [on hold]
I have a clock that runs on 3 D batteries and, as you can imagine, it's a pain to maintain them. I've found a DC adapter that delivers 4.5v (1.5v x 3) but it doesn't budge when connected. I imagine ...
0
votes
1answer
19 views
Verilog code synthesis error
I'm having problem with my verilog code when I synthesize it. It shows multiple drivers error. I think may be it's because of multiple always blocks I'm using in it. So how can I fix it!!? Here it is:
...
2
votes
2answers
59 views
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 ...
1
vote
2answers
38 views
Single supply inverting amplifier
I am using this circuit to measure the voltage of a small solar panel - around 3 or 4 V max (so instead of the photodiode consider there is a solar panel). That means Vin = -3 V. When I first built ...
2
votes
0answers
52 views
RC LED “Bathroom occupied” indicator
I want to build a little LED indicator for my bathroom door. The basic idea is that when a person sits or stands next to the toilet, a little transmitter signals it wirelessly to the LED diode which ...
1
vote
1answer
36 views
Arduino - Controlling Electromagnets/Solenoids
I'm a French student and today I have to control some magnetic things with an Arduino.
It seems to be electromagnets, but I'm not sure, since I'm a complete novice to electronics.
I saw some ...
2
votes
0answers
36 views
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 ...
0
votes
0answers
29 views
Is there any significant difference between the couple of photointerrupters and a reflective?
This may sound a little bit silly though.. but I do hope you guys can give me a little bit of tips if u do have any? :)
Which kind of optical encoders you think is the easiest to use if I am to ...
0
votes
0answers
23 views
Using TPA3122 as a headphone amp
So, long story short, I ordered two sample chips from Texas instruments and they inadvertently sent me 25- and were nice enough to let me keep them. I'm still finding uses for them, and it crossed my ...
-5
votes
0answers
32 views
i have problem with my vhdl code [on hold]
i want vhdl code by which i can when click on push buton first led become on ana 7_segment displays 1 when click again on push buton no led light but seven segment displays 2 and then when click again ...
0
votes
2answers
40 views
Will the large gate current when turning on/off power mosfets with gate drivers cause problem to limited current power supply?
I have a idea using Arduino to control power mosfets(CSD18532). After considered some problems about wiring power mosfets directly to Arduino pin, like considerable slow switching time, I turned to ...
1
vote
1answer
30 views
Can I use the ATtiny84 ADC0 pin as both input and output?
I am using the ADC0 (PA0) pin of an Attiny84 to read analog values from an audio circuit. This part is working fine. Since I need to connect the Attiny84 to 8 LEDs, I'd like to use the ADC0 pin as an ...
0
votes
2answers
61 views
Planning to make a pen-like device which has a roller rolling on a surface and measured its linear distance travelled
I am planning to use a microcontroller to do the brain works of receiving pulses from the encoder and compute it to output linear distance and at the same time indicating the measured distance as ...
0
votes
2answers
49 views
RC Low pass filter [on hold]
I have a question in my EC subject like:
Assuming there is a series RC circuit connected to a sinusoidal voltage source with a peak-to-peak value of 8V & frequency of 10kHz and a DC offset of 2V, ...
0
votes
1answer
23 views
What values can I change when replacing a 200uH 2Amp coupled inductor?
I am replacing a coupled inductor (with corrosion on it) on a liquid handling robot board, in hopes to fix a blowing fuse problem. The part number is not coming up in any search I have tried so far, ...
0
votes
1answer
64 views
Is it OK to trickle charge a disposable battery
So I am playing around with designing a UPS when another question hit me.
If I have a source feeding a small amount of current into a non-rechargeable battery is this OK.
By OK, I mean is this ...
0
votes
0answers
8 views
Dimmer not turning bulb on or off [migrated]
I'm connecting a dimmer.
There are four wires coming from the wall. 2 black (one is HOT). 1 White. and 1 ground.
There are four wires on the dimmer switch I bought. 1 black. 1 red. 1 green ...
1
vote
4answers
876 views
Why can't one battery power an infinite number of leds (or anything else)?
If voltage is equal across parallel resistors, then why can't one battery supply power to a infinite number of leds, if they are all in parallel?
0
votes
3answers
59 views
Powering 16 super bright blue LEDs with Arduino
What is the best way to power 16 super bright LEDs using an Arduino Uno to achieve max brightness?
Each LED has the following characteristsics:
...
0
votes
0answers
13 views
TI CC1101 Wireless Module Problem
I'm using CC1101 wireless module breakout module with msp430 launchpad. I have two kits I want to make communicate.
I'm able to communicate with the TI library. But the modules behave strangely. ...
-2
votes
0answers
25 views
Homemade Wireless HDMI transmitter/receiver [on hold]
Several products out there but not a single explanation/schematic... Can someone please point a way to actually build one of these? Video and audio....
0
votes
3answers
72 views
Is there a type of Switch that is open until Armed?
I'm designing a circuit that will need to be off until the user decides to 'arm' the circuit. It should then always be closed (and hard to hack into the on position).
Does a certain component exist ...
0
votes
1answer
34 views
Shunt capacitance in applications not involving photo diodes
I have read a lot of articles about how to determine the correct feedback compensation capacitors capacitance in transimpedance amplifier circuits, but they "all" use the photodiode as an example.
...
0
votes
0answers
42 views
Trying to figure out how to solar power an embedded device
I have an Arndale octa board which itself needs 5V 3A power supply. Then I have four (4x) DC 5V motors and a 5V servo, and a number of other peripheals. So I think 5V 5A is safe to assume?
I want ...
1
vote
0answers
43 views
How to transmit HDMI audio and video by wireless means [on hold]
A friend and I are working on a project and we need to be able to transmit and receive wireless audio and video signals at a very fast rate. The most convenient method we can see right now is HDMI. I ...
0
votes
2answers
41 views
Help with wiring of stereo jack
Could someone point me in the right direction. What I'm doing here is I took the insides from a cheap Bluetooth speaker and I would like to rewire it to an headphone jack (male). I have the cable ...
1
vote
1answer
39 views
Proper oscillator for CPLD
I plan to use KC5032A40 as a clock source for CoolRunnerXPLA3 256. I power it with 3.3V and interface it as suggested:
I perform the measurement at the Test Point and do not add any CL capacitance, ...
0
votes
3answers
32 views
Replacing usb speaker circuit with LiPo battery & Bluetooth. Not sure what watt audio amp to use
I have a set of Logitech usb speakers which I wish to convert to bluetooh speakers. A usb has the the power, ground, data+, and data- connections. Which i believe cannot be simply replaced with a ...
7
votes
3answers
459 views
A Question about Resistance, and Learning for Beginers
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 ...
2
votes
1answer
59 views
Operational amplifier circuit with one ac and one dc voltage source
The following circuit contains ideal operational amplifier, Vs voltage is sinusoidal with amplitude of 1Volt and frequency of 1kHz, where VE is a dc voltage of 2Volts.
I am trying to use ...
2
votes
2answers
243 views
Voltage regulator vs. voltage controller
I frequently meet the references to voltage-regulators and voltage-controllers. However, looking at the specs I find them to perform the same function. Is there a difference between the two, or ...
-4
votes
0answers
44 views
HDD brushless motor driver [on hold]
I would like to drive a 3 phase (4 wire) motor out of an old hard drive, and be able to manually adjust the speed. but i have limited supplies.
I only have: 555 timer, 4017 decade counter, various ...
1
vote
1answer
43 views
Implementing dynamic frequency scaling on PIC32 by changing PLL multiplier/divider?
I read in the PIC32 Reference Manual that one can change the PLL multiplier and divider at run-time, provided that the input frequency is between 4 and 5 MHz and the resulting frequency does not ...
-4
votes
0answers
62 views
Mosquito racket circuit [duplicate]
As I know, the transformer can work only with AC supply. But in this mosquito racket circuit, I see the power supply is DC. I don't understand why.
I see an oscillator stand before the transformer, ...
1
vote
1answer
49 views
NRF24L01+ false detection
I use a NRF24L01+ module configured for receiver, 3-bytes address, 1-byte CRC, 1 Mbit/s, channel 2402 MHz, 2 pipes listening. Addresses are non-trivial (0x525443 and 0x4d4252).
But when transmitter ...
0
votes
0answers
13 views
Can a DIY balloon become a danger to others? [migrated]
A couple of years ago I remember reading that a DIY group sent a 25$ balloon 20km into the air. This made me think for a while because if they lift about 5Kg that high It would generate more or less ...
5
votes
2answers
353 views
What exactly is “dominant” and “recessive”?
I am reading data sheets on the LIN bus, but apparently the same terminology is used for CAN.
What does "recessive" and "dominant" stand for, e.g ...
0
votes
2answers
74 views
Are AA battery and 18650 battery the same? [on hold]
I have an Antex SZ004W0 wireless soldering Iron which uses three 1.5V, AA batteries, but I don't know if it supports rechargeable batteries. I know that it supports non-rechargeable battery named ...
0
votes
2answers
68 views
Question regarding PCB design layout of Raspberry Pi
I have query regarding PCB design layout of Raspberry Pi (RPI). I wanted to know how LAN9512 chip is connected to Ethernet RJ45.
I found one of PCB layout picture which suggests there is line on PCB ...
0
votes
2answers
58 views
Main speaker specs to consider
For a 20W amp, what are the determining characters, apart from speaker Impedance and Power rating, that affects a selection.
Example Specs -
(source - ...
