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I have a Rigol DS1104 oscilloscope. Last week I stood up quickly from my table and saw a spike on the scope. Right now all the channels have a DC offset when probe is connected to ground or unconne...
I have no experience designing for Intrinsic Safety (IS), but need to do that now. I have read thru IEC 60079-11, which seems to be the relevant standard for my purposes. The board I need to desi...
How do I find the voltage of the capacitor and the current through the capacitor after the switch is closed?
I was hiking around the Berkshires in western Massachusetts yesterday, and came across this metal panel where some power lines were crossing a ridge: The panel is a few meters wide, and appe...
I have been observing these little cases hanging to the wires from a long time. They are almost everywhere here in India, but I was unable to find out what they are. I am not sure whether they are...
In monostable multivibrators we use a trigger signal applied to the base of the transistor which is usually off to enter the astable region Can we instead have a pin which is connected directly ...
I've seen a few different circuits (a) (b) (c) (d) described as "an O-ring circuit" or "an optimal O-ring circuit". What does the "O" and the "ring" refer to in such circuits? How do "O-ring circ...
I have designed a graph of the current in a photoresistor related to the brightness of light which hits the photoresistor. Our professor told us that it is more correct to draw the Current/Brigh...
I have learnt that if we have 2 parallel conductive plates and we seperate them the capacitance is increased if we put a good conductor between the plates. Now the resonant frequency of a inductor...
I'd like to use a 555 timer as carrier wave generator at ~ 50 kHz and modulate the amplitude with an external digital signal at ~ 1 kHz. The pulse width remains constant at 10us (50% duty cycle)....
I was watching a video from EEVBLOG about bypass capacitors, and he presented a theory that randomly connecting different values of capacitors in parallel can create unexpected impedance spikes: ...
As we know there exists numerous different kinds of PCB CAD software. The big ones seem to be Eagle, KiCAD, Altium, OrCAD, Solidworks, DesignSpark and probably a few more. When it comes to mechani...
Suppose we have this circuit which is supposed to be an unbalanced frequency mixer. But how does the diode generate a signal with new frequencies at the output?
Here is a video of the AN/PRM10, and here is a schematic (I believe the image can be zoomed): As most commercial grid dip meters produced in the past, this one possesses several functions in ad...
In the block diagram of this pulse oximeter design guide , in page 6, I see that the system utilizes two analog filters, one for filtering the PPG signal generated while the RED light/wavelength is...
The current through the tunnel diode is: where $I_{f}$ is the current from the Shockley diode equation and $I_{tunnel}$ is the tunnel current. Is there an expression for the tunnel current or i...
I have a question about this circuit:(critically damped oscillation) For a critically damped oscillation for a series RLC circuit the equation of current has this form I(t)=D1te^(-at)+D2e^(-at) ...
I have a problem which I don’t understand how to solve. I have this 2-bit adder, but when I select A1AO to be (11)2 3 and B1BO to be (11)2 3 and run it on Logisim it doesn’t show me 6. Instead it s...
If I connect a battery to an LC tank and then to an antenna and then on the other side at a distance x, I connect an antenna to another LC tank and this to a diode and this to an LED, Do a I have a...
I find the current flowing through the capacitor $$\begin{align} I_{C_1}(t)&=\dfrac{\mathrm{d}}{\mathrm{d}t}\left[V_1(t)-I_{C_1}(t)R_1\right] \\ {}&= \dfrac{\mathrm{d}}{\mathrm{d}t}\left...
I just want to know why the Linear time-invariant(LTI) systems are a rich class in Signal Processing. Ofcourse there are different systems but still LTI is stressed a lot in academia. Is there any ...
Assume that I have some generic antenna connector, followed by a pi-filter/50ohm impedance matching components, then a DC blocking cap (as per the RF switch recommendations) and then a RF switch fo...
I am trying to build an active-low digital isolated switch capable of withstanding 32VDC voltage without creating any damage to the system. This is the snapshot of the circuit not fulfilling the r...
I saw that this PCB socket: Is marked as pressfit for non-plated holes. However, can it be used with plated holes as well, or will it damage the plating inside?
I have no record in electrical engineering; this is a total outsider question which might be grasped absurd. Wikipedia defines EMP as: An electromagnetic pulse (EMP), also sometimes called a tr...
I'm trying to modify a LED torch, and there is a DC-DC booster (1.5 V to 3.3 V) and after that some SOT-23 device which (I assume) keeps constant 90 mA current through LED. I know I could remove th...
What is a difference between SPI stream and memory mapped SPI? PS SPI is a peripheral.
I am trying to test a AD8307. Here are my connections: (pins not shown are left unconnected, and also pin 8). I get a quiescent output voltage at pin 4 of about 850 mV with respect to ground, w...
I have a PIC32MZ2048ECG064, a 64-pin 32-bit microcontroller with 512kB RAM. This is not enough for my purposes, I need to extend it by at least 32MB, preferably 64 or 128. I believe this means I ca...
Usual values used in doing electronics/power supplies are almost always round numbers: 5V 12V 28V 48V 60V I understand that in some cases ICs are built to accept the voltage directly comi...
I'm designing a PCB for a project. 12 volt input power supply is provided externally, so the user will buy a power adapter, so putting a popular DC jack on the PCB is the best choice.
While doing some reading on RF designs I ran across this paragraph: I have never designed an RF circuit, but all the PCB trace antennas I have seen on development boards are square. For example,...
I HAVE A METER LIKE THIS BEHIND MY HOUSE MY NEIGBOR SLOWED IT DOWN SOMEHOW HE SAID HE OPENED IT UP AND DID SOMETHING TO IT NOW HE PAYS LOWER ELECTRICAL BILLS THAN ME BUT HE HAS COLLEGE DEGREE IN ...
Nowadays, that I videoconference over WiFi a lot, I've started to notice some trends in WiFi quality. And it seems my connectivity decreases when my microwave oven is on (I work in the same room a...
One of the ceramic capacitors that I've found(link to the capacitor) specifies the following characteristics at 10 kHz: The difference in value is quite significant, almost 100 fold. Which grap...
Since am interested in how a delta sigma modulator works, I need to know what is the difference between differential amplifier and differentiator if there is a difference of course.
I recall vividly a story told by my grandfather who worked with high voltage power lines. A worker drove heavy machinery into 700kV line and then jumped out of the truck, instantly combusting upon ...
In this bistable multivibrator which is $Q$ and which is $\overline{Q}$?
The question being asked Ultimately, I want to know why the output voltage wasn't the expected (via calculation) 11.72V when the estimated drop-out voltage at the ~0.1A load was about 200mV. The i...
Imagine a battery pack with <=60VDC of maximum voltage and a load of up to 10kW of power(the PMSM inverter with the input capacitance of up to 1mF). The load is not always known - could be 100uF...
In the circuit below, I am applying a $3.3Vpp$, $63kHz$, 50% Duty Cycle, PWM input signal at the gate of the mosfet and I am expecting to see a similar waveform with different amplitude at the LED...
In a previous question we found that for a critically damped oscillation: $$ I(t) = 2 t e^{-0.5 t} $$But if we integrate to find the voltage through the capacitor: $$ V_{CO} + \frac{1}{C} \cd...
The particular IC I ran into this issue with was DS3231 RTC. The pin configuration shows: However, the datasheet specifies To my knowledge, 'N.C' appears on ICs when it is decided to use a cer...
Moderator's note: This is getting ridiculous. You keep posting these drawings that are barely legible. The scribbling is bad enough, but the uncropped images are unacceptable. The image you ori...
I want to make a simple 7MHz direct conversion SSB receiver in order to materialize some RF concepts I have been teaching myself lately. My question revolves around the mixer portion. I'm failing t...
I want to run a specific motor in the open loop. How to calculate the maximum ratio of V/f to run it? Am I looking at Ld or Lq value for this? Let's say these are the characteristics - haven't ch...
I have a battery pack that consists of 18650 battery cells(14 cells in series max.). Hence, the voltage of the battery pack will be between 35V and 60V(to be on the safe side) I am designing a BMS...
Sensorless BLDC motor controller are becoming more and more popular, especially with rising of the drone industry. Being able to detect where the rotor is at 0rpm or no load seems intuitive if we ...
How can we find the equation of current and voltage of a capacitor circuit if the input voltage is AC without using the impedance formula Xc = -jωC?. We have for homework to find the equation of...
I see a lot of common collector amplifiers with the output taken across an emitter resistor. What is the purpose of doing it this way instead of connecting your load directly to the emitter? I sh...
