All Questions
0
votes
0answers
9 views
Unipolar stepper motor and a MCU
I have been trying to steer unipolar stepper motor (5V, 0.7A) using microcontroller powered only by USB (5V or smthing like that). The motor clicking got louder but the motor doesn't move yet.
I ...
3
votes
0answers
24 views
Op-Amp Sample and Hold Circuit Help
So, I'm trying to modify a sample and hold circuit from "The Forrest Mims Engineer's Notebook", that uses a 353 op-amp, so that it runs off of a single supply:
I needed to add a 4.5V (1/2 supply ...
1
vote
1answer
20 views
Lifting electromagnet & Induced EMF
An electromagnet is lifting/pulling large pieces of iron, from a distance $r$.
Is there an induced EMF in the coils of the electromagnet due to the change in flux?
Another configuration would be the ...
0
votes
1answer
56 views
DIODE as capacitor?
How does Diode act like a capacitor when voltage across diode is less than forward voltage spec. Basically when diode is turned off? What is its usual capacitance when diode (zener) is turned off.
0
votes
0answers
17 views
Where does Vcc-2 comes from in ECL. Is it the max requirement of spec to keep the BJTs in ECL in active mode all the time? or is it something else?
In ECL logic devices, what is Vcc-2 voltage you usually terminate with? I mean where does Vcc-2 comes from. Is it the max requirement of spec to keep the BJTs in ECL in active mode all the time? or is ...
0
votes
1answer
27 views
Crystals as RLC circuit? How?
What gives the crystal oscillator a property of Inductor? How does energy transformation between electrical field and mechanical stress and strain makes oscillator work like a Inductor? I know how ...
0
votes
1answer
26 views
Choosing Oscilloscope with appropriate bandwidth for Jitter analysis
Can someone give me a rule of thumb of choosing Oscilloscope with appropriate bandwidth for the Jitter analysis of clock signals? What device is highly preferable: spectrum analyzers, frequency ...
2
votes
0answers
18 views
dsPIC 33EP128MC506 will not read RB8, appears to be software problem
I'm using a dsPIC 33EP128MC506. I have two PCBs with this chip, both displaying the same symptoms, implying it's not one-off damage. RB8 is definitely being driven to 3.3 volts, confirmed with a ...
1
vote
1answer
23 views
In Eagle, why is the tstop layer larger than the pad itself?
Why is the tstop aperture around a pad larger than the pad itself? I would have imagined that it would be exactly the same size, or slightly smaller, so that the solder stays only on the defined pad. ...
0
votes
2answers
34 views
A question about Diode Clamps
I was just wondering out of curiosity... In the following circuit, if I were to supply a steady DC voltage to Vin and another to the Offset input, would this be true:
Vout = Vin - Offset
1
vote
1answer
24 views
STM32F4 - Digital Signal Processing ( DSP )
At this website, I have read that STM32F4 microcontrollers have DSP instructions. To quote:
It also implements a full set of DSP instructions
I am beginning to learn embedded C programming with ...
1
vote
2answers
17 views
Controlling 7W 12-14V power LED with Arduino
I'm trying to control a 7W 560MA 12-14V COB LED Strip using Arduino. When I connect the LED directly to a power supply at 14V (using 1 ohm limiting resistor) I have 0.56A / 12.3V on my LED. But if I ...
0
votes
1answer
18 views
Moore's law: relationship between transistor count on an integrated circuit and minimum feature size
I'm doing a project about Moore's law, looking at physical limits of the technology / materials we're using (photolithography for example), the limit you'll come to is the minimum feature size.
For ...
0
votes
0answers
21 views
What files/directories are needed to recreate a Actel/Microsemi Igloo2 project?
This question is along the lines of What files/directories are needed to recreate a Xilinx PlanAhead project? but for an Actel/Microsemi FPGA design. I'm looking for a fairly standard design with ...
7
votes
2answers
279 views
How to graduate from Arduino to using a microcontroller directly?
I've been working on an Arduino project. After I get everything working using the Arduino, I would like to move to a solution that does NOT use Arduino. That is, I would like to use a microcontroller ...
1
vote
1answer
22 views
STM32 Timer to control GPIO
I'm trying to output a slow clock (4kHz) on an I/O from the STM32F0. I'm wondering what the advantage is (if any) of using one of the timer pins to output this clock vs toggling another GPIO on the ...
0
votes
1answer
31 views
Radio antenna isolating transformer
I need to isolate galvanically my antenna from my RF transceiver. For this I have been recommended a transformer, I select a 1:1 transformer operating in high frequency range. Is it enough to wire it ...
0
votes
2answers
57 views
What type of analogue circuits are only possible on an IC and not using discrete components [on hold]
The main benefit of designing on an IC is that the transistor parameters (e.g current gain) shall be very close for the different transistors that exist on the silicon die in close proximity. This ...
-1
votes
2answers
48 views
Why is OCR1B values are not stored? [on hold]
I have following program to control two servo motors:
...
2
votes
2answers
41 views
How is abstraction used in Analogue circuit design?
Digital circuit design is a domain in which we abstract a complex analogue transistor circuit as a logic gate, effectively abstracting away even the electrical nature of the device as we use boolean ...
-1
votes
0answers
37 views
Is there a free digital circuit simulator for MSP430? [on hold]
Prototyping with real components is very time consuming.
In order to save time, I have been looking for a digital circuit simulator, compatible with the MSP430, with no success.
How do professionals ...
-3
votes
0answers
33 views
Magnetic Levitation system control using Altera FPGA [on hold]
I want to design a controller to suspend a magnetic levitation ball in air using FPGA,I have some matlab simulations deals with my design and bringing the levitated ball to its desired position from ...
1
vote
2answers
36 views
CMOS 4066 Question
This is my first post here and I have a question about a CMOS circuit I have been designing for I while using the 4066 (I'm a noob to digital electronics). I am using a 4066 to pass random pulses I ...
-3
votes
1answer
29 views
impact of inductor and capacitor at resonance [on hold]
It is said that inductor and capacitor cancle each others effect during resonance bt do they still have any effect on the circuit??
-5
votes
0answers
44 views
Which calculator should I buy? [on hold]
I am an electrical engineering student and need a calculator for doing basic engineering jobs like -
pole zero to transfer function conversions
gradient, diversion, curl of vector functions
...
0
votes
1answer
29 views
How does iPhone detect when dock connector is connected to an audio input? [on hold]
I'm trying to solve a seemingly simple problem with (hopefully) an equally simple solution. I'm strictly an amateur when it comes to electronics, so I'm hoping someone here can guide me in the right ...
2
votes
1answer
44 views
What happens when you connect hot and cold sides of Peltier device together?
I would like to know how the Peltier device would act if you heat sink the hot side WITH the cold side. Would it just sit there and consume power?
I need something to consume ~15 watts or more at ...
2
votes
3answers
53 views
why the quantised of DAC will affect the amplitude of the output waveform of AD 9850?
By referring to the http://www.analog.com/static/imported-files/data_sheets/AD9850.pdf,
for page 9 and figure 5,
why the quantized D/A converter affect the amplitude of the output waveform?
0
votes
1answer
42 views
Apparent power definition
What is the definition of apparent power?
How to calculate apparent power for three-phase circuit? Is it S = S1 + S2 + S3 or S = sqrt(P^2 + Q^2)
where
P is total active power P = P1 + P2 + P3
and
...
2
votes
1answer
32 views
Door phone audio signal to pc soundcard
I need to interface door phone system to a pc soundcard to listen and talk to the external unit.
The door phone to interface is an as yc/200 of BPT and its a classic analog 4+n wires Door phone ...
-4
votes
0answers
37 views
Make mobile flashlight on and off in 30 mSecond for 5 minute [on hold]
I am developing an app that with make mobile flashlight on and off in 30mSecond for about 5 minute, now my question is: "does it hurt mobile flash?"(any electrical problem?)
1
vote
1answer
78 views
What happens to a transformer if the supply side is shorted?
Suppose I have an industrial plant, where a switchboard is fed through a transformer. The switchboard have only "passive" loads, i.e. they don't contribute with short circuit currents.
If there is a ...
0
votes
4answers
64 views
Simple broadband RF generator [on hold]
How to make a generator of RF signal which have multiple signal outputs ?
Details:
...
-4
votes
0answers
30 views
potentiometer to adjust o/p of battery charger [on hold]
I have designed a battery charger having o/p 10V / 600mA . Now i want to use the same charger to give variable o/p of 5.1 V to 7.2V using a potentiometer in the o/p. Please suggest how should i use it ...
0
votes
0answers
16 views
L4970a output oscillates when load is removed
I need the following: 24V vehicle input. Allow for 28V. 13.8V @ 10A output. I used an L4970a. My circuit delivers the load, no problem.
On initial switch on with no load, the output is stable. ...
-4
votes
0answers
36 views
Explain what does this statement “X PIN 22 ISTYPE ‘reg’ " mean? [on hold]
I know what “Y PIN 23 ISTYPE ‘com’ ” means as the statement describes Y available at output pins 23. The Y variable is a ‘Combinational’ output available directly from the AND-OR gate array output. ...
2
votes
1answer
86 views
Best method for impedence matching?
Impedance matching is one of the major application of common collector configuration. Is Common Collector configuration the best method for impedance matching? why?
-1
votes
0answers
39 views
Push-button with transistor [on hold]
Transistors can be used as switches. I need a push button job to run the monostable mode of a 555 timer. I want to turn the mode with digital logic circuits, so I cannot use a microcontroller. ...
2
votes
1answer
40 views
Audio from Arduino Due's analog outputs to line-in
Line inputs are high-impedance, Wikipedia says around 10kΩ. Due's DACs provide 0-3.3v (actually less) and are rated at 3mA max. \$\frac{3.3\rm{v}}{10\rm{k\Omega}}=0.33\rm{mA}\$. According to ...
0
votes
0answers
40 views
How do you build a sequence detector using D flip flops?
I have to build a mealy machine sequence detector of the sequence 1001 (with overlap allowed) in LogicWorks using D flip flops.
I've drawn the state diagram on paper. It looks like:
I think I need ...
2
votes
2answers
91 views
How to determine required voltage of a lightbulb
I have a bulb here that has no markings except it says 25 watts, I just wanted to know what voltage does it need to power up. Our standard voltage here is 220 V, I tried plugging it on a 110 V ...
2
votes
1answer
37 views
difference between POR and other resets
everyone.
I would like to ask you about the difference between Power On Reset[POR] and other Resets because in PIC18 controller datasheet i have seen a statement like:
...
4
votes
2answers
66 views
Audio from Arduino Due's analog outputs using LM386
Due's DACs provide 0-3.3v (actually less) and are rated at 3mA max. As far as I know, common speaker/headphone impedances range from 8Ω to a few hundreds, so driving these from the DACs will destroy ...
0
votes
1answer
34 views
Middle-Tapped Transformer Full-Wave Rectifier Vs. Full-Wave Bridge Rectifier
In terms of output voltage, which one of these would be best? Coming into this, I would have to say the center-tapped transformer full-wave rectifier would allow the most accurate output voltage ...
3
votes
3answers
208 views
STM32F4 - Floating point unit ( FPU )
I would like to know, what is the purpose of the special FPU unit, that is advertised with STM32F4 microcontrollers ?
To quote this website :
" The Cortex-M4 core features a Floating ...
1
vote
0answers
34 views
Adjustable oscillator using 74LS04
I'm looking for a schematic to build an adjustable oscillator using the IC 74LS04.
I'm not very expert.
I've found this schematic:
Is possible to achieve something similar? I'm looking to make an ...
0
votes
1answer
41 views
What is the best way to measure op amp input and output impedance versus frequency?
How do I measure the input and output impedance vs. frequency for an op amp?
2
votes
1answer
83 views
Is there a standard for writing device drivers for microcontrollers?
I have written device drivers for microcontrollers using AUTOSAR. But I was interested in knowing if there are other standards for device drivers. I am planning to write for TIVA TM4C123GH6PM. It has ...
0
votes
2answers
47 views
Deriving simple voltage equation
$$Vo = (Vs*R2)/(R1*(1+R2/Rl)+R2)$$
I need to derive this equation given this circuit:
And this is what I have so far. Where am I going wrong?
$$I=Vs/(R1+(R2*Rl)/(R2+Rl))$$
$$V_RL=I*Rl$$
0
votes
3answers
53 views
Is rms value of a positive varying DC voltage same with its mean value?
I know that rms of an AC is totally different than its mean. But what if the voltage is not alternating(DC) but varying by time. For example a noise with a huge offset.
How is varying DC measured by ...
