All Questions

13 views

Rs232 to SD card

I need a device that logs data coming from an rs232 port onto an sd card, I know their are arduino shields that could be got to implement this but I am in a hurry and need something ASAP. Does anyone ...
11 views

What is the difference between disturbance and noise for dynamic systems?

In most references from dynamic system theory, the following linear continuous dynamic system is considered. $$\frac{\text{d}x(t)}{\text{d}t}=Ax(t)+Bu(t)+Dd_{1}(t)\quad (1)$$ y(t)=Cx(t)+Ed_{2}(t) ...
19 views

How does adding two Resistors in Series contribute to the sum of its resistances

I would like to know why by adding two resistors in series we would get a sum of it's resistances.I know by Ohm's Law that since $R=\frac {V}{I}$ it's certain that ...
5 views

Units of area parameter in ngspice

Can anyone tell me what are the units of area parameter used in ngspice? Urgent need!
11 views

Electrical power simulation/analysis software [on hold]

What is the most appropriate software tool for an electrical engineer that wants to play around and understand the intricacies of electrical power generation, transmission and distribution. Required ...
41 views

what frequencies do caps filter?

I've been trying to find out what frequencies get filtered out by which type and capacity capacitors, but cannot find simple rules that say "type X, cap Y filters xxx (k/M)Hz - yyy (k/M)Hz". Yet ...
12 views

Accessing RS232 Rx Tx instead of OTG on stellaris LM4F232H5QD evaluation board

I am asking two related questions here: I can see a program uart_echo for stellaris lm4f232h5qd . What I want is that I need to access this data on teraterminal using PA1 and PA2 pins instead of ...
25 views

Debugging a PIC16F84A interface with a 4N25 optocoupler

I have a PCB board that I'm trying to repair, the principle of this circuit board is to switch an oven relays one at a time only with a constant rest time, and the switching time is predefined by the ...
78 views

Shall I connect inverter with boat GND?

A friend of mine is building a boat. On this boat, he has 12V batteries with a 230V/13A transformer. Recently somebody suggested he should connect the null with the ground. With DC, this is common ...
33 views

How does the power supply noise generated by digital ICs affect the output of regulator?

I have learned that the digital ICs would generate the power noise in the power supply line,however, I am not so clear about how. In my opinion, two contributors: the change of the current would lead ...
23 views

How the Depletion Region is shrinked when Diode is in forward biased?

I would like to know why does the depletion region gets shrinked when a potential is given to a diode(Forward Bias).Is it because we have given a higher voltage than the voltage of the depletion ...
29 views

Adding more current to circuit [on hold]

I have a high voltage supply (aprox. 20kV) and I would need to increase the current while keeping the voltage. Is there any way you can think of or is it impossible? Thanks.
26 views

Why feedback is needed in PLL FM Demodulator?

I am trying to build FM Demodulator in FPGA. The architecture I am trying to use is PLL-based FM Demodulator like the one below. I searched for the working principle of this demodulator but there is ...
29 views

trouble getting two PICs to communicate via I2C

I'm having a bit of trouble getting two PICs to communicate with each other over an I2C line. Both are 16F886, one sitting in the PIC 28-pin demo board, second one sitting inside a board which I ...
19 views

Use a headphone jack to activate a 'silent' speaker

I am looking for a type of speaker (around the size of a coin) that connects to a smartphone or walkman (for example) which plays silent tones or pulses. Like a miniature speaker that a person can ...
31 views

Why does an Ohmic contact contain non rectifying junction?

I would like to know a simple explanation for the term 'Ohmic Contact'.I looked in wikipedia but I couldn't get what actually it means.I couldn't even get what do you mean by non rectifying ...
21 views

battery charging

I have: -12V 7.2Ah,sealed lead battery,valve regulated -solar panel 12v with 100mA my question is,how long does it take to charge this battery by using this solar panel?
30 views

Function call isn't executed in verilog

Why function call to clogb2 is not being executed in the following code. I don't get any compilation errors but still parameter ...
18 views

Are all connections to my ENC28J60 required?

I'm trying to connect a ENC28J60 module that exposes a SPI interface to my Beaglebone Black. I only have pins 1, 2, 3, 4, 5, 10 connected to my Beaglebone's SPI1 interface and I've used the following ...
44 views

Questions on Operational Amplifiers & Bridge Rectifiers

What I've learned so far from Navy school is that operational amplifiers are used as a substitute for transistor amplifiers and they contain three main circuits: the differential amplifier, common ...
321 views

What is the difference between different types of GND

I would like to know the difference between different types of Grounds like AGND, SGND, Battery Gnd, PGND. Are all the grounds not same? Cant we connect the device to any one of these grounds?
9 views

anybody help me regarding adding noise source in to tanner tool and measure Static noise margin [on hold]

I have started with tanner 15.1 tool. i couldt find how to add noise sources in to the circuit,to calculate STATIC NOISE MARGIN.
34 views

synchronous buck converter

!I have designed synchronous buck converter circuit for 48v to 12v conversion. LT regulator IC is used for regulation. Maximum load current is 4A. I am increasing load from 1A to 4A stepwise. I am ...
26 views

Why resistance should be increased for Photoresistor in night for Street Lamps?

I can't get why the resistance for a Photoresistor should be increased at night time as said in Photoresistors. The reason is that I think that to turn on a light it's better not to have a higher ...
21 views

I have a Metex M-3650CR multimeter and have just replaced the fuse and the fuse it takes is a Fast Blow 2A 250V, now my problem is that the multimeter constantly displays OL (Overload) on the screen ...
21 views

85 views

What happens if I supply a higher voltage than the rated voltage of my jack?

I want to replace the original jack from my notebook with a new one since it is broken (and I would like to avoid to replace it with the same as the original). The original AC adapter supplies 19V and ...
69 views

Why is the digital out acting as ground on arduino?

I was following LED Light bar project in Arduino Project handbook and I noticed some odd behavior in the Arduino. I accidentally didn't ground the back half of the breadboard (because I didn't ...
35 views

Problems with Infrared circuit on a PCB - Is it the board or schematic?

I am using the toner transfer method to apply my circuit for 6 sets of infrared emitters and collectors connected to an RJ15 cable on a PCB for use with a Raspberry Pi B+ board (connected via IDE ...
21 views

Help needed driving an old PIC programmer from Raspberry Pi GPIO

I have been trying to use a Raspberry Pi's GPIO pins to drive an old PIC programmer board that used to have a parallel port connection before I started messing about with it. You can see from the ...
47 views

Using a microcontroller as a microcode sequencer?

There's this thing called the weird processing unit, or WPU. It's basically an idea of various experimental processors (architectures) that try to be interesting, new, original, extraordinary, ...
22 views

The timing-driven placement phase encountered an error

Could someone explain inexperienced VHDL coder what this error message trying to tell me in simple words? I found a similar question here, but here was no answer to it: ...
51 views

Determine the maximum load of a power supply

I am trying to upcycle an old bit of tech I had lying about. The main part I am looking to recycle is the power supply however I do not have specs of the power supply itself. I have measured an output ...