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H: Buffer op amp amplifier saturation
I have designed a buffer amplifier using an LM358 op-amp, with an input of a 1kHz sine wave and a power supply of +/-6V. whenever I increase the input sine amplitude above a certain threshold, I get a weird output (unlike the normal saturation that we all expect such as the one in... |
H: Do datasheet specs for a dual diode refer to both diodes in series or to the individual diodes themself?
The question: With a dual diode such as the MMBD3004S (datasheet here), are the ratings such as reverse breakdown voltage specified for each diode individually, or for both the diodes combined? There don't appea... |
H: How much current for a 5V 60 LED/m WS2812B 5m LED strip?
I'm planning on controlling a 5m 60 LED/m WS2812B chip 5V strip with a Raspberry Pi Zero W. According to the website it draws 18 watts per meter (90 watts total). What current would this strip draw, and what would you recommend on powering both the Pi and the... |
H: Questions about the voltages of a lithium jump starter I purchased
I purchased an Audew jump starter based on several favorable reviews on youtube.
According to the specs, the jump start output is 14.8V, but when I check the voltage with my multimeter it measures 16.3V.
The jump starter also has a 15V/10A output fo... |
H: 8X1 MUX using Verilog
I am trying to write a design and a testbench Verilog code for a 8X1 MUX with input width of 8 bits each.
Here is my design code :
module MUX8_1(
input [7:0] a[8],
input [2:0] sel,
output reg [7:0] y
);
always @ (sel) begin
case (sel [2:0])
3'b000 : begin y [7:0]<= a [... |
H: LCD backlight connection, K pin connected only
I have been trying to build the attached schematic, and my issue lies with LCD backlight.
The designer has attached the cathode (K) pin, but not the anode (A) pin. This did not work for me. It is an old schematic, and is designed for an LCD with only 14 pins + A and K... |
H: What are these four pin components labeled LB-4 on a motor control circuit from 1979?
This board performs the speed control logic for a 3 HP shunt-wound DC motor driver in a CNC mill built in 1979. The spindle turned on intermittently last week and then stopped working, so I'm reverse engineering the circuit to deb... |
H: AC-DC High voltage converter
I don't have much experience with power electronics but I'm trying to design a power supply with AC 220Vrms (311peak) to DC 1500V converter to charge a capacitor in 50 miliseconds (and keep charging it, since it'll discharge as soon as it reaches 1500V).
Conventional transformer + bridg... |
H: Linear Circuit and System Interpetation
My question is about interpreting a given circuit as being itself a linear system. We know that a linear system needs to satisfy the superposition principle: if \$f(ax_1+bx_2)=af(x_1)+bf(x_2)\$. This means that a zero input should result in a zero output. Circuit components l... |
H: bridged emitter follower - how does it work?
I built a rough test version of the above circuit, it is intended as a bridged (i.e 'balanced') unity gain buffer for headphones.
The test circuit seems to work, as in there is sound and it is not blatantly distorted .
The op amp outputs in the circuits are from the bal... |
H: Why is my set up short circuiting?
Disclaimer: I'm a noob.
I have the following schematic (updated as per @Transistor):
I had first tried this out on my breadboard. It worked fine. From what I read online, this was two capacitors set up in parallel.
When I do the setup on a PCB prototype board, it short circuit... |
H: ngspice simulation : random signal source
I'm new at the ngspice simulator and I don't understand this line of a Netlist that I found
Vn 1 n1 dc 0V ac 1mV trrandom(1 5us 0s 125m 0m)
if the random signal is only used in the transient simulation why did they keep the ac signal with an amplitude of 1mV ?
AI: It's ju... |
H: Switching 12V 2A witch raspberry pi 3.3V
I've bought an LED strip with 3 Colours. Each colour schould be switched individually. Sadly I couldn't find any Mosfet suiting my applecation and I'm not really good at finding Mosfet's or drawing Scematics. The Mosfet should be able to:
Switch fully on with the 3.3V from... |
H: Terminology of AC -DC converters
I would like to ask about the difference between the terms "AC-DC Converter", "DC-AC Converter" and "Inverter".
If I am getting it right, the "AC-DC converter" converters AC voltage to DC.
The "DC-AC converter" turns DC into AC.
The inverter can do both?
To be more specific I am w... |
H: Thermocouple amplifier and cold junction compensation
I am trying to design a thermocouple amplifier with cold junction compensation. I already designed a simple amplifier for the thermocouple using LM358. Note that I can built this entire circuit using only cheap and easy to find components, such as low power tran... |
H: What is the purpose of this polygon arrays on PCB?
I'm interested what is the purpose these polygon array on below picture.
Thermal management?
Thanks for the help!
AI: It's called "copper thieving". The copper is added to areas with low density of copper to create a more even distribution across the board. Even ... |
H: Buck Converter with RLE Load
I am trying to calculate the duty cycle of the buck converter as in the figure for discontinuous conduction mode of operation. I have worked to the math and have got the following graph as in the picture-
The Duty cycle depends on the load current. How we find out the on time if we... |
H: 4 Layer PCB Altium - 2nd Layer Ground, others Thermal
I read since a long time but never had an account, now its my turn to ask a question on here:
I have an idea but currently unsure if that works technically or if it is good design:
1st (Top Layer) : SMD Devices + Routing
2nd Layer : Ground Plane (only Gro... |
H: What is the theory behind these current equations? (for Z paramaters)
In the photo below is shown the method for deriving z-parameters of the circuit. Apologies for my badly drawn values for resistors as they weren't shown in the original image. Basically I'm struggling to see where the parts in red circles are com... |
H: how the comparator amp works as integrated amplifier
I need some explain how does comparator work as zero cross detection and integrated amp
AI: 1) There is no comparator, instead the LM324 is a very slow quad opamp.
2) The 1m resistors are a dead short, they are probably 1M which is 1 million ohms.
3) The total g... |
H: Induction motor starting torque and pull out torque
Recently I was doing some work on the induction motor where I found some general theory on starting speed torque curve of the induction motor. Where the theory is the starting torque will be 1.5x of rated torque & pull out torque will be 2x. Is this the always a c... |
H: Risk of long-term shorting XLR cable
I'm adding a 'mute switch' into my XLR cable.
To mute an XLR cable/Phantom powered microphone you temporarily connect pin 2 and 3 in the cable to short the connection. I have seen plenty of youtube videos and tutorials online of people doing this to add quick mute buttons and st... |
H: Charge indicator with comparator - very sensitive to noise
I need an indicator when the current from my charger is larger than 100mA. I tried the below circuit but this seems very sensitivity to noise. Probably I am getting some ripple in the mV range from the charger.
Is there a more robust, less sensitive way to ... |
H: What is the orientation of the pins in this drawing of an L4940V5 TO-220?
I am a novice trying to build a circuit using a L4904v5 voltage regulator. The datasheet has the following images:
This 2D pinout drawing gives me few clues about which side I am viewing it from. I assume it was viewed from the side is "... |
H: Which one is the correct symbol of enhancement type MOSFET?
I studied MOSFET from ' Electric Devices and Circuit Theories by Robert L. Boylestad ' The symbols of depletion type and enhancement type MOSFET are given below from the book.
But recently, in the book of Sedra/Smith named Microelectronic Circuits, I ha... |
H: Multiplying oscillator signal with a pulse
I am trying to multiply my oscillator sine signal with my pulse. But, the voltage of the oscillator is too big so it saturates.
This is the output I am getting from my oscillator. I am getting the required 100kHz frequency for my oscillator by would like to reduce the vol... |
H: LTSpice simulation issue
I am studying a circuit which will charge a capacitor till using a voltage doubler till it reaches a specified voltage value. Then it will discharge through a resistor. An SPDT switch is realised for this function using 2 SPST switches. A behavioral source is used to control these switches.... |
H: Syntax error near "else" in Verilog, in an initial block, next to assert
I'm trying to make a self-checking testbench for an ALU I'm designing for an extra credit assignment. Here's what I have:
module testbench();
wire [31:0] a, b, y;
wire [2:0] f;
wire zero;
alu test(a, b, f, y, zero);
initi... |
H: Is it possible to drive a power piezoelectric in lower frequency than its own frequency?
I am driving a piezo transducer simply by an inductor series with piezo.
the resonant frequency of the piezo is about 40KHz and I designed a 20KHz transducer.
I'm giving a pulse voltage (using a class E driver) to drive this se... |
H: 4940v5 drop-in replacement for LM7805?
I am a novice who purchased several TO-220 L4940v5 chips thinking they were drop-in replacements for the inefficient TO-220 7805s that I've been using. But not a single one seems to work. No heat, no voltage output, nothing. Thinking I had the pins backward I tried a fresh o... |
H: Why can an AC circuit breaker not be used in DC circuits?
Let's assume that I want to use a 20-amp GE AC circuit breaker in a DC circuit. So, after testing it in a DC circuit with some loads and ammeter + clamp DC amp meter I find the current at which the breaker trips. Let's assume as an example this is 45 amps. S... |
H: What is the Purpose of the Clock?
There are many examples of logic circuits that have the clock signal, such as the JK flip flop and the clocked SR NOR Latch, but I still wonder what is the purpose of the clock. Why do people think of adding the clock signal into the circuit? Isn’t it simpler and easier to learn wi... |
H: Limiting the current with the LM2679
I'm building a power supply, and I'm trying to see if the LM2679 will fit my needs. I like how it's similar to the LM2596 as well as the fact that it has a pin to limit the switch current. However, I have a question regarding the relationship switch current limit and the max out... |
H: Multimeter diode mode: do different multimeters show the same results approximately?
I think that in many cases the voltage that a multimeter shows in diode mode is dependent on the current it uses for that mode. So the values measured by different multimeters in diode mode should be different in many cases. Am I r... |
H: Why is the LTspice cut-off frequency for my multiple feedback low-pass filter not matching?
I am designing a 6th-order multiple feedback low-pass filter with the cut-off frequency at 1000 Hz. I wrote a Matlab script that calculated the capacitor and resistor values.
I combined all transfer functions together and go... |
H: plotting dirac delta function using inverse Fourier transform
I was trying to plot shifted dirac delta function in Matlab.
$$\begin{align}\mathscr{F}\left(\delta(t-t_0)\right)&=\mathcal{F}(\omega)=e^{-j\omega t_0} \\
e^{-j\omega t_0}&=\cos\omega t_0-j\sin\omega t_0\end{align}$$
Using Trigonometric form of Fourier ... |
H: Maximum error of nominal resistor combinations
Suppose you have resistors which have nominal values of \$R_0\$ or \$2R_0\$ but can vary to be anywhere between \$(1 ± .03)R_0\$ or \$(2 ± .06)R_0\$, respectively, so each can have about 3% error.
Is it correct to calculate the maximum error of two possible combinati... |
H: why is \$P^{max}_{Z_L}=|\hat I_L|^2\times 4\$,not \$|\hat I_L|^2\times 5\$,when \$\hat Z_L=\hat Z^*_{th}=4-3jΩ\$
What is the max power of \$\hat Z_L ,P^{max}_{Z_L},\$ when the \$\hat Z_{th}=4+3j Ω\$??
First i know the Imaginary part of impedance will cause Reactive Power,so the real power can't be the same as the... |
H: Motor specifications - how to compute allowable running time for power levels between the continuous and peak specs?
Say a motor is rated for 20 N·m continuous torque, and 35 N·m peak (peak = for no more than 30 seconds). Alternatively it may be specified at with continuous/peak currents, but if the motor efficienc... |
H: why is \$|V_C|=90\$, not \$70\$? series RLC circuit
If \$|V_S|=100V\$,\$|V_R|=60V\$,and \$|V_L|=10V\$,then what is \$|V_C|\$ ?
simulate this circuit – Schematic created using CircuitLab
My solution
\$100=\sqrt{60^2+(10-V_C)^2}\$,so \$(10-V_C)^2=80^2\$,so \$(10-V_C)=80\$,now we can know\$V_C=10-80=-70V\$,so \$|V_C|... |
H: Problem with custom USB microphone
I developed a MEMS microphone based audio capturing device and transfer that audio via USB to the PC. I used Audacity opensource software to test my working and found the audio plays well when recorded and I play back the recorded sound but has static/crackling noise during the li... |
H: How to model voltage controlled switch in LTSpice?
Having trouble making a Buck converter using two complimentary switches in LTSpice. I've got everything laid out exactly as perscribed, but when I run I get the following error:
"Can't find definition of model "SW""
I've put the model for each one right there, so ... |
H: High bulk capacitance (100.000 uF) discharge time on Wifi router supply
I want a WiFi router, those supplied with 12V x 1~1.5A AC-DC wall adapter, to remain ON for a short time (maybe one second or a little more) after the AC mains gets its energy interrupted, when AC goes down.
One idea is to place 10x electrolyti... |
H: Simple DIAC circuit which I do not understand - LTspice
Here is the circuit :
Here is the model and the parameters of the DIAC :
.SUBCKT DIAC DIAC_IN DIAC_OUT PARAMS:
+Tr=0.342
+Vbo=13.6V
+Delta_V=19V
+Ibo=15uA
*
*Tr: Rise time (in µs)
*Vbo: Break over voltage
*Delta_V: Dynamic break... |
H: Designing a triac based regulatable DC supply
I need about (30V-160V)32A DC for my project. I am trying to build an electronic circuit to regulate AC mains (220V, 50Hz) to produce voltage from 30V to 160V and rectify it to produce DC voltage. With some inspiration from circuit diagrams posted online, I have designe... |
H: How to model and understand the asymmetry of a parallel RLC circuit spectrum
I'm working with some parallel RCL circuits and I have noted that when I record a power spectrum (so \$\rm{dB}\$ vs \$\rm{Hz}\$) that the spectrum is asymmetric:
As I'm sure you all know if we calculate the impedance of a parallel RCL ci... |
H: Why is GPU memory fixed?
In pretty much all modern computers and mobile devices, the CPU can have varying amounts of memory (either to be configured by the user or fixed at point of assembly). Apart from historical form-factor reasons (where GPUs just came as 'a card' that was actually composed of the GPU itself, p... |
H: ADN8810 control frequency from Arduino Due
Resurrecting a 3 year old project. I'm skilled software engineer but new to electronics so it's a bit of a walk in the wood at night without a flashlight. The pcb has a ADN8810 - 12-bit current source with an adjustable fullscale output current of up to 300 mA. My understa... |
H: Spherical waves in far field region
in my antennas book (I do not put its reference because it is not in english) it is written that, at high distance from the source, the electromagnetic field radiated by it is a spherical wave.
This can be shown by analyzing the expression of the EM field at high distance generat... |
H: Verilog output is hiZ in testbench
I'm new to verilog and modelsim. I'm having trouble with my AND and OR modules in this particular testbench. The output is always Z(hi impedance)
module mux2to1_tb();
reg[1:0] r0,r1;
reg r2;
wire[1:0] out;
initial
begin
r0=1;
r1=3;
r2=0;
#10;
r2=... |
H: Is there a full list of the names & abbreviation of electronic components
I came by a few electronic components that I don't recognize them from their shape nor their letters printed on the PCB. Is there a full list of the names and abbreviation of electronic components?
Some of the letters that I don't know their ... |
H: Problem with LTC3872 Voltage Converter. Simulated results not matching with information provided in the datasheet
I'm trying to make a boost converter that takes an input of 3.7V and outputs 5V. I found a chip that I think will work well, the LTC3872 by Linear Technology.
In the datasheet they give an example ci... |
H: External vs arduino power supply for servo motors?
I recently built a project that involves the control of three SG90 servo motors. I started off by controlling this through the 5V output pin of the Arduino Uno, with the Arduino powered through the barrel plug with a 9V mains power supply.
However, the servos could... |
H: Without the use of any software, what would be the cheapest way to connect my broken laptop's keyboard to my desktop?
I am trying to use an old keyboard from a laptop as a new set of keybindable keys for my desktop. I will worry about software side later what I need here is this: How can I use the keyboard from my ... |
H: ESP8266 / ESP32 - Health issues
I am doing a pretty specific project, where I plan to connect up to 150 devices, mostly depending on ESP32 and a few ESP8266 devices.
All of them will be located in a tiny space of around 5-8 square meters.
Are there any research or norms (like ISO in Europe) that touches that topic... |
H: What are press-fit pins used for?
I found a this DIP socket that has "press-fit" pins. What are these actually used for? Are they literally used as a replacement for soldering? If so, why would anyone do this since that would seem to decrease permanence and increase cost?
https://www.mill-max.com/catalog/download/... |
H: Meaning of "no exposed metal in this area" on connector drawing
I am looking at the mechanical drawing for the JAE WP7B-P050VA1 connector, and it has the following drawing suggesting a PCB footprint:
My question pertains to the "no exposed metal in this area" note: does this mean that I am not allowed to run any t... |
H: The proof of \$PF_{p}=cos\theta_p=sin\theta_s\$
There is a Series RC circuit ,which power factor is \$\frac{\sqrt{3}}{2}\$,now if i modify this "Series" RC circuit to "parallel" RC circuit,then what is the value of power factor of this circuit?
The answer shows me that
\$PF_{p}=cos\theta_p=sin\theta_s=\frac{1}{... |
H: Extracting 25W from a pair of 18650 li-ion in series
If I have 2 bats of li-ion in series. 8.4V full charged and 6V full discharged. What should be their minimum mAh capacity, if they are 18650 size, and considering a constant load of 25W.
25W/6V = 4.16A?
Would they heat much at that power?
AI: What should be their... |
H: What is the purpose of ferrite or inductor on the voltage input of FTDI chip?
I bumped into a couple of strange symbols that look like inductors or ferrite beads, I'm not sure what this is. Does anyone know what it is and what is the purpose of it? My guess is it has something to do with a general use of USB as a p... |
H: Is my thinking right for the simple harmonic circuit
If this is a simple harmonic circuit, then what is the \$X_C\$?
I know harmonic circuit means that there is no value in the imaginary part of the impendence or admittance, that is, \$Z_{th}=R+0j\$ or \$Y_{th}=G+0j\$.
In this question, if the circuit wants to be ... |
H: Why output voltage becomes less when beyond resonating frequency?
In a class C amplifier (Figure A), every time the transistor turns on in every "pulse", the collector current becomes saturated. This charges the capacitor to its maximum (Vcc). This capacitor will always get charged to its maximum, independent of th... |
H: Why do we use 2 transistors for each path of a MUX in CMOS?
Below is the schematic of a CMOS level 2to1 multiplexer. As you can see that if we want to choose A0, we set S input as Logic-0.
My question is that what happens if we remove one transistor from each path. PMOS from C0 path, and NMOS from C1 path. Doesn'... |
H: ISO 7637 Supply Transient pulses - Explanation
I am trying to design an input power supply filter circuit inorder to protect from ISO 7637 pulses.
I am referring this Little fuse app note
There seem to be different pulses. Pulse 1, 2a, 2b and so on.
In page two of the app note, they have given the description of th... |
H: Find the average power dissipation of the load
I have given the following voltage and current waveforms.
I am required to find the average power dissipation of the load.
I know \$ P_{avg} = \frac {\int_0^T \mathrm{v}\mathrm{i}\,\mathrm{d}t}{T} \$
I have trouble finding the equations for the waveforms.
Please... |
H: Reverse voltage in LED buck converter circuit
The circuit
simulate this circuit – Schematic created using CircuitLab
Everything is fine except when the switch is open, I measure ~-3.5V on the points marked.
Why is that and is it dangerous for other components that get powered by the 5V after the switch?
The module... |
H: RLC circuit and equivalent load resistance of a transformer
I would like to know when there is no more energy into the RLC circuit with the transformer. (R in RLC circuit symbolized the resistance at the secondary). I tried to simplify this model by doing an equivalent circuit without a transformer. Then It will b... |
H: How can I replace a SN74LS04?
I came across Ben Eater's Youtube channel and website and thought I'd give the clock circuit a shot (possibly doing the entire 8-bit computer thing in the future). He conveniently put list of items online what's in the kit. I wanted to order it from him, but shipping is quite expensive... |
H: Steady-state Error Definition
In the textbooks and reference material which I have been using during my course on control systems, a common definition of steady-state error is as follows:
$$E(s)=R(s)-C(s)$$
where E(s) is the error (and also the signal carried forward directly from the summing node), R(s) input and ... |
H: Is it possible to have a register with multiple drivers?
This is just a theoretical question I have. Imagine we have a register (a reg signal in Verilog for example) and two possible inputs that have to write to that register. I am assuming all signals are synchronous to the same clock. Normally in these cases I gu... |
H: Subwoofer high level connection and Class T amplifier
This question has a connection to a previous one of mine:
I have a BK Electronics Gemini I subwoofer that will soon be spare. It has two inputs called: low level and high level. The low level input is a pair of RCA connectors that may be connected to a suitab... |
H: How to detect if the logic PCB can successfully communicate with the power PCB
In most devices (As washers, refrigerators etc.) you find a logical board (The one the user interacts with and mostly has the buttons and a digital or an LCD screens etc.) and you find the power board that that has the transformer, triac... |
H: Basic code using millis() function to calculate time elapsed
I do not know why the simple code below does not work. It may have to do with how unsigned long behaves?
Code simply determines if elapsed time has exceeded Snooze_Time which is 10000 by comparing the current millis() to the start value of millis().
unsi... |
H: Max7219 and Common Anode Displays, choosing the correct transistors
I've got some common anode 7 Segment displays that I want to use a Maxim 7219 IC to drive with. The Max7219 is designed for direct driving common cathode displays but Maxim do have an app note that describes using the chip to drive higher current a... |
H: cascading shift registers 595 vs 594
Simple question, i need to use 3 shift register to control 6 analog switches and 12 leds with only 6 digital outputs, nothing difficult BUT my IC provider doesnt have the clasic 595 in DIP package, so i was wondering to use a 594. Because i'm using analog switches for analog sig... |
H: Creating ladder PLC logic using force inputs and outputs
I am currently using Allen Bradley PLC and RSLogix Micro to program it. The problem is:
Create a ladder logic diagram for the following problem in which pump #1 and pump #2, alternately or
simultaneously, pump liquid.
• When the level switch closes, first pu... |
H: Simplest way to limit current from MCU pin
I'm trying to build a very simple flyback power supply capable of only about 1mA. The basis is to supply a PWM wave to a 1-1 sepic inductor (shielded coupled inductor).
The problem is that it would be easy for the inductor to saturate and essentially short to ground.
It f... |
H: Impedance matching for broad bandwidth voltage amplifier
I need some basic advice for impedance matching: I have a photodetector (Det01CFC from Thorlabs) that generates a current. For my experiment, I would like to amplify this signal with an amplifier. The amplifier that I can use is the LNA-1440 with an input imp... |
H: Using an LSM6DS3 IMU with a LiPo battery power supply and LDO with Enable
I am trying to build a circuit containing the LSM6DS3 IMU (Datasheet) to be powered by the Sparkfun 110mAh Lithium battery PRT-13853 (Datasheet).
According to the datasheet of the IMU, it is able to operate in a voltage range from 1.71 to 3.6... |
H: Using DDR4 RAM instead of SRAM
Currently I am using the internal BlockRAM from a FPGA to safe the samples I am getting from an ADC with a frequency of 200MHz. In the future, I want to use equivalent time sampling to get a virtual resolution of around 500ps.
The BlockRAM has a size of a few MB. I want to safe around... |
H: Can I use a ferrite bead instead of a resistor on the data wire of my LED strip?
I have a WS2812B[PDF] LED strip which I want to control with the PWM0 pin (GPIO18) of my Raspberry Pi.
Multiple sources highly recommend to insert a 330-470 resistor in between the data pin of the controller and the DIN of the first LE... |
H: Why is my pullup resistor more noise immune than a pull down?
I have a circuit that appears to have some noise problems related to stepper motors I'm driving. When I changed some switches to use pull up instead of pull down resistors, I get better results. Why?
I'm using a PCF8574 digital IO expander for some limit... |
H: How should I size the transistors in the class AB linear amplifier
If I want to design a class AB linear amplifier as the following one, how should I determine the width of the pmos and nmos?
Class AB amplifier specifications:
Vdd: 6V
Input: 0.5V to 5.5V
Output voltage 0.5V to 5.5V
Output current: -450mA to 450mA
... |
H: resistor combination circuit
simulate this circuit – Schematic created using CircuitLab
This is probably a very stupid question. I am new to electrical engineering in general, I was working with NOT transistor gates in order to make a simple SR Latch and came across this case. D2 and D1 in my circuit are both pull... |
H: Is there a way to permanently assign 0 to one of an array of registers in verilog?
Is there a synthesizable way to permanently assign the value to a particular memory location? I need a reg that is fixed at 0 and cannot be written to. All writes should be ignored and the register must remain 0.
AI: The following wi... |
H: Chip antenna too good to be true?
I have the following setup:
Very small PCB - 25mm in diameter that hosts chip antenna;
I feed directly into antenna matching network with about 7.5cm coax via ufl connector;
There are no other components on the board as I'm testing antenna only.
I use miniVNA Tiny to get some mea... |
H: Can I change the voltage (12V) input into my optocoupler to 24 V?
simulate this circuit – Schematic created using CircuitLab
I have an inductive sensor (LJ18A3-8-Z/BX,) normally open 6V to 36V 300mA. It is connected to a 12V 80kHz single channel opto-coupler. At the moment it is connected to a 12V DC power supply... |
H: Is the voltage accurate?
The question is Find the Q-points for the diodes in the circuit using the ideal diode model:
The book solution is:
However, per my analysis both diodes are conducting because if as assumed that D1 is cut off the voltage at D1 cathode side would be -3.92 V which is less than the voltage fo... |
H: Transistor current limit
Suppose the DC motor has a peak current of 500ma and after that it drops to 100ma, the transistor can switch continuously 200ma.
If I limit the current of the transistor from the base current to 100ma, for some reason could the transistor consume a higher peak than that when starting the m... |
H: Inductor not working
I tried building a toroidal inductor with the following parameters:
OD= 1.400 in / 35.55 mm +/- 0.75 mm
ID = 0.900 in / 23.0 mm +/- 0.55 mm
Ht = 0.500 in / 12.7 mm +/- 0.50 mm
Wire: solid insulated copper 14G
Data sheet for the material: https://www.fair-rite.com/43-material-data-sheet/
For so... |
H: 12VDC Fan rated at 0.08A only drawing 0.04A, can I increase current draw in order to bring the rpm up?
I've built a small desktop fume extractor for soldering.
It uses a 120mm 1000RPM, 12V, 0.08A case fan. Not huge, but it does the job.
The fan is only drawing roughly 0.04A and I have been fault finding and theory ... |
H: What is the difference between Continuous-Time and Continuous Value in signals?
I do not understand the difference between Continuous Value and Continuous-time. Discrete-time and discrete value. Can anybody offer a clearer explanation?
AI: I do not understand the difference between time & value
Time is along th... |
H: Is my Inverse z-transform solution method accurate?
The question is as follows:
The book answer is as follows:
However, my approach is as shown below I even cross checked my partial fraction and it was correct.
Please tell me where is my mistake?
Ok. Below is my revised trial after Mr. Any pointed where was my... |
H: Determining node voltages and ladder currents in R-2R DAC Ladder with Op-Amp
I'm really curious about the voltages at the nodes between the R resistors in the R-2R DAC ladder with an Op-Amp. I've tried using KCL and Ohm's law to find them, but I haven't been able to. Simulation shows different results.
The voltage... |
H: Is the there a KiCAD plugin for making automatic board outlines?
Is there a plugin for kicad that can make simple shaped board outlines automatically? For example rectangles, rectangles with rounded edges etc.
I think that could be super usefull. Beacuse at the moment I edit the cooardinates of the lines manually t... |
H: Offset problems with charge amplifier
I have a question about designing a charge amplifier.
I am currently using this simple setup for my application. As input, I can use several commercial piezo-based accelerometers. I need a pretty wide bandwidth (up to 0.1Hz). Instead of a high valued resistor (which would be ... |
H: Recreate "Voltage gain vs Frequency" graph of Op-Amp in LT Spice
I am trying to recreate the "Voltage gain vs Frequency" graph of the LT1037 Op-Amp in LT Spice. According to the datasheet page 6 the graph looks like this: -
Trying to recreate this in LT Spice gives me a graph, that doesn't match the graph above: -... |
H: Isolating and instrumentation Amplifiers, does the order matter?
I've been reading up on the concepts of properly isolating sensitive signals in applications like analog front ends.
For small signals, it is appropriate to use an in-amp. I understand that. But what about isolation?
It seems (see figure below) most f... |
H: voltage direction confusion
This may look notoriously trivial to ask.
we can see the direction of electron flow as indicated in the picture.
the down side of the arrow must be the positive side of the voltage drop in each resistor, so two positive voltages + v_be=0 it implies v_be is a negative (-0.7 approx.). but... |
H: Difference between a DC SSR (solid state relay) and AC SSR
I am trying to understand the difference between a DC and AC solid state relay. For electromechanical relays, I notice that they are often rated for some VAC load and a smaller DC load. Solid state relays, however, seem to be rated only for VAC or DC.
What ... |
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