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H: Servo motor always limited in range?
I am reading up on (servo) motors to start to play around with them. It seems to be that all servo's are limited in range. Most have a 180 degrees range I read.
This would mean that the shaft of a servo never rotates a full cycle.
Is this really the case or I am missing the obvi... |
H: What makes an active buzzer oscillate?
All I can find online are descriptions on how active buzzers have an oscillator built in so that you just need to feed them a DC and they buzz at the frequency set by such oscillator, but I haven't been able to find either a diagram, description or teardown of an active buzzer... |
H: Altium - How to disable white (polygon?) outlines during interactive routing
I seemed to have pressed some hotkey activating a white outline around same layer objects during interactive routing. See image below. It seems to slow down FPS quite a bit, so I'd like to disable it. Can someone tell me (1) What the white... |
H: What for are two resistors and one capacitor when attaching an audio CD drive output to a TDA7318, but not for Line In?
I'm trying to build a TDA7318 audio mixer chip into my automobile infotainment system. Now I've found a similar project, where the output of the CD drive is attached to the chip by using two resis... |
H: MOSFET: Cannot control gate signal using Arduino PWM
I attempted to power a 100mA LED with my Arduino. The power for the LED was provided by a battery (3.0V) - tge Arduino was connected via USB to a computer.
The idea was to use the Arduino PWM to regulate power from the battery to the LED.
Wiring the N-channel Mos... |
H: Confusion about relationship between energy per coulomb, and the amount of coulombs in current
I am trying to understand how a power supply works and working from the ground up I am learning about electricity, voltage, current, amps, and wattage. I am new to this stuff so I apologize if this is an easy or already a... |
H: Is any signal ever one way
I am trying to confirm a suspicion/understanding about electrical signals, and especially One-way CONTROL signals i.e. specifically NON-Power type signals in electronics like,
Trig/Echo pin in UltraSonic Sensor,
Digital IO line on an application specific IC/Sensors feeding into a microco... |
H: Create Transformer Center-tap From 2nd Secondary
After ordering this 200VA, 32V transformer, I realized that it doesn't have a center tap on each secondary, which I need to have. (duh on my part) So I want to use 110V across the 220V primary leads to give me half the voltage at each secondary, resulting in a single... |
H: Tap controller implementation in JTAG
I’m looking at a TAP controller for the implementation of JTAG, but I’m not sure what which part of the diagram the top left circuit is refeering to.
Are the boundary scan cells just D-flip flops?
AI: The item in the top left of the graphic looks very similar to the boundary s... |
H: LCR meter weird datasheet
I have a LCR meter. In the datasheet there is a measurement frequency given for the inductance measurement. But not for the measurement of the capacitance. Is the frequency for the capacitance measurement not important?
AI: While both capacitors and inductors have a performance that can va... |
H: Replacement for 50+ year old solder fuse technology
I am refurbishing an old automotive clock (VDO Kienzle) that uses an internal low-melting point (~120 degrees F) proprietary solder "fuse". Is there a way to calculate or estimate the size of a suitable modern automotive fuse replacement, specified in amperage?
AI... |
H: My daughter's science project is to charge AA batteries with a solar panel
We bought a 0.5 watt solar panel with 4.5 V, a 4 AA battery holder and a 15 ampere Schottky diode 45V , and 4 lithium ion rechargeable batteries.
We connected the red positive solar wire to the diode. We assumed the end of the diode with the... |
H: Calculating the power lost per foot from “\$I^2R\$ losses"
I am currently studying The Art of Electronics, third edition, by Horowitz and Hill. Exercise 1.6 says the following:
C. Power in resistors
The power dissipated by a resistor (or any other device) is \$P = IV\$. Using Ohm’s law, you can get the equivalent ... |
H: UART receiving random values
I tried to transmit "S" using De0 nano FPGA board and UART over USB module . The problem is i am not receiving "s" constantly . I am using the software Called Hterm to see receiving data.
When i remove the USB to UART module from the PC and reconnect the receiving value changes.
After... |
H: Colpitts Oscillator - Supply/Output Voltage
I try to simulate Colpitts oscillator but i got stacked about one thing. When I simulate this circuit, the output Vpp is 24 V in other words, it oscillates between 0 V and 24 V. The question is, we give 12 V DC supply voltage to the circuit and we get 24 Vpp output voltag... |
H: How do you decide on having more than two layers to have on a PCB?
I just started writing my bachelors thesis. I have been working as a junior hardware designer for a little less than a year now. All the boards I have designed until now have 2 layers. For my thesis I will be designing a board around the new Raspber... |
H: Can this low-pass filter for audio possibly work without a power source?
In MOSQUITO: Covert Ultrasonic Transmissions between Two Air-Gapped Computers using Speaker-to-Speaker Communication, M. Guri et al describe a malware capable of bridging air gaps and creating a bi-directional covert channel by turning connect... |
H: I2C bus with different voltages slaves
I have one MCU powered with 3.3v acting as an I2C master in the BUS and 4 slaves, one of them is 3.3v logic and the others three are 5v logic.
It's ok if they share the BUS, connecting the 5v devices to the BUS using a MOSFET level shifter and the 3.3v device directly to the B... |
H: What is the irregular signal at the bottom of this "spectrogram"?
I am reading research papers about LoRa, and I have come across the below figure in this one.
The horizontal axis is clearly labeled frequency, but the vertical one isn't. I recognize the chirps in the middle, so I understand that the vertical axis i... |
H: Current drawn by MQ9 Sensor
Here is the datasheet of the MQ9 sensor
I would like to be sure about the current drawn by this sensor. The datasheet doesn't say anything about that, but tt says the power Ps heating comsumption is about 340mW and the heating time is 60 to 90s
Is the current drawn just for 60 to 90s (o ... |
H: Sensing 24v AC with 4N35?
Basically I have sliding gate which has contacts to turn lamp when it's open or closed (two different ones) that are rated 24v AC max 3W.
I would like to use those contacts to know if the gate is open or closed. I'm a total newbie in electronics, googled a bit, and found that what I probab... |
H: Class AB Amplifier - Weird oscilloscope output
I have built this little kit for a class AB Amplifier. This is the schematic if you do not want to follow the link
It works fine, I can hear decent sound.
I then tried to check the output with an oscilloscope to learn a bit more. I am using a bitscope micro USB oscill... |
H: How do causality and stability affect the response of a linear time-invariant system?
Suppose that there's a linear time-invariant system with the following transfer function:
$$H(s) = \frac{1}{3(s-2)}-\frac{1}{3(s+1)}$$
If the system is causal and stable, I can determine \$h(t)\$ by simply evaluating the Laplace t... |
H: Recharging a Li-ion battery while using it
Right now I am designing a circuit that will charge a Li-ion battery via USB, using the MCP73831 (at 100 mA).
The battery voltage (nominally 3.7 V) will be regulated to 3.3 V to power a microcontroller like an ATtiny85 or ESP8266 for example.
Below is what I have so far. M... |
H: Power consumption LCD display on digital watch 12h/24h
just a fun question:
When I was a child, I thought that displaying my casio F91w in 12h mode rather than 24h will make my battery last longer since there are fewer segments displayed.
when i saw this graph i realized it wasn't that simple.
Does the energy consu... |
H: Ideas for driving an electromagnet with high voltage AC current from a PCB
I have an aquarium pump that is no longer being used and I want to integrate it into a design of mine. I am inexperienced designing for stuff with high voltage AC or AC current in general. i've done many <12V DC electronics designs, even com... |
H: Regarding PCB IFA microstrip antenna mirror image on ground plane hole areas
This is regarding the adjacent mirror image formed over the ground plane by a PCB antenna during operation. Take the first image of the IFA with the ground plane highlighted in yellow on layer 2, the top signal layer is hidden in the image... |
H: How to measure high frequency with an oscilloscope without loading circuit down too much?
I am experimenting with building a high frequency common emitter circuit shown here. It operates at 144MHz and it should have around a gain of 4.
Here is the simulated circuit. I do not have any load resistor attached yet (kno... |
H: STM32F407VG Discovery + CMSIS HSE Clock Configuration
I am trying to program an STM32F4 discovery board using Vscode, Platformio and CMSIS. However, I cannot set the right clock frequency. I have programmed it to blink an LED every second, except it seems to be blinking every 3 seconds.
This is my desired clock con... |
H: Cannot find this 6 pin IC 362J38
I have a power brick I'm trying to repair but have been unable to locate a 6 pin IC 362J38 that I suspect is the issue. No other faults found except the fuse after going over the board 3 times. No visual clues. All e caps, mosfets removed & checked. Opto is good. Not sure what the ... |
H: Increasing Amplification using a MAXIM MAX492 Op Amp?
I'm using a Maxim DAC (the MAX541) with a TI microcontroller. I output a digital audio signal from the microcontroller to the DAC. I have the DAC's output hooked up to a typical 3.5mm audio jack. When I plug the 3.5mm jack into typical computer speakers the v... |
H: I'm losing data when my Raspberry pi talks to its USB connected Arduino
Some very simple code, which I got somewhere on the Internet
Arduino:
void setup() {
Serial.begin(9600);
}
void loop() {
if (Serial.available() > 0) {
String data = Serial.readStringUntil('\n');
Serial.print("You sent me: ");
S... |
H: Why does adding one more extension cable turn the MCB on again?
I found a strange phenomena when I tried to use a metal cutter that consumes about 2000 watt.
See the following illustration.
If I just use one extension cable, the MCB will trip when I turn on the cutter. However, if I add one more extension cable, e... |
H: DC blocking capacitor value for 2-12GHz?
I'm working on a simple RF mixer circuit, and having some trouble picking the right DC blocking cap value for 2-12GHz (even higher if possible). Here's the schematic for the front end LNA:
C7 and C9 are what's giving me problems, especially C9 since it's part of the bias-T ... |
H: How to shutdown op-amps for low-power standby
What is the best way to shut down the analog front end of my sensor system for a low-power standby mode. My circuit is battery powered via a 3.3V buck/boost converter I would like my STM32 microcontroller to shutdown the analog circuitry (op-amps) before going into low-... |
H: Inverting Amplifier Not Applying Gain to Bias Voltage
I am simulating an inverting amplifier circuit (Page 3 in this app note) with LT spice. The amplifier has a gain of 10 V/V and since I am using a single rail supply, I am applying a bias voltage at the non-inverting input of about 0.113 V.
I expected the bias v... |
H: Wave disappearing on oscilloscope
I am trying to observe a wave on my oscilloscope (with a CRT display). I can see a point on the screen tracing out the waveform, but the wave does not stay on the screen for me to say. This wave is very slow (only 1 Hz). Could that be the problem?
I have linked a video of what I se... |
H: Generator synchronization to grid and angle difference
Following conditions are needed for generation synchronization :
1 Phase Sequence
2 Voltage Magnitude
3 Frequency
4 Phase Angle
I have question about Phase angle assuming that the frequency is the same and there is a big phase angle then the phase angle will n... |
H: AC, Negative instantaneous power x Wh consumption measurement
If a load is connected to an AC power source, and the current wave on it is shifted from the voltage wave of the power source, for some periods of time the instantaneous real power (Vinst x Iinst) will give a negative instantaneous power value, due the v... |
H: HDMI for Jetson Nano contradictions in guides
For my drone, I want to develop a custom Jetson carrier board with minimal required interfaces. For quick debugging, I would like to add an HDMI port on the PCB. However, I’m not familiar with HDMI and I found some contradictions between guides.
In most guides, it’s wri... |
H: Galvanic isolation in multiple battery design
I'm trying to design a board to control a couple of DC motors (or stepper motors) for a small robot. The device will integrate a control logic based on a uC and the necessary H bridges for the motors. DC motors speed will be modulated with ~1 kHz PWM signals.
No great p... |
H: Transformer Magnetization Flux
As far as I understand, an ideal transformer wouldn't show any net flux inside its core, as any such net flux would induce electric fields and in turn currents in the windings such that it will disappear. So an ideal transformer would show no (net) flux at all, correct? So it would ki... |
H: Active highpass filter for microphone, how to choose cutoff frequency?
I am currently taking a class on filter design, and I am learning by doing.
I want to make a small project by building a microphone circuit.
I found online a tutorial by Great Scott. He made a circuit like this. His results were pretty good so I... |
H: Using an optocoupler to drive a pulse counter
I am trying to design a circuit to measure the RPM of a small internal combustion engine.
The ignition on the engine is a simple magneto style ignition. These ignitions are switched off by grounding a wire. When not grounded, the wire carries a signal that pulses once p... |
H: Identifying a 6 pin and a 18 pin WSON IC
I have a couple of the following ICs, which I suspect to be some DC/DC converter possibly from TI, but I could not find the exact part number. It is a 6 pin, WSON package IC with a thermal pad.
The top says:
48D6K
L197B
The other IC is a 11 pin QFN one where 8 pins are G... |
H: 74LS multiplexer outputing 2V as LOW
I'm using a 74LS257 to select between 2 4-bit buses, but instead of 0V it's outputing 2V.
Here's the schematic:
The problem appears when Reading is logic 1 (selecting Actual). If Actual0 is logic 1, @0 outputs 2V. All the inputs are 0V or 5V (the problem lies in the IC's output... |
H: CMOS Buffers minimum voltage for logical high
I'm looking at the datasheet for a non inverting CMOS buffer CD74HC4050 What is the lowest voltage that can be placed on 1A to cause 1Y to be logic High? I know it's somewhere in the datasheet but I new to this and don't know which value. Thanks
Datasheet https://www.ti... |
H: USB on/off switch
I have this LED light strip which has AA Battery converter with a USB female output port. I will attach picture below. I would like to know how can I connect a SPST on/off switch to the light strip so that I can easily turn the lights on and off. Do I just tap into one of the power wires in the US... |
H: What is the critical current density of indium tin oxide ITO?
What is the critical current density of indium tin oxide ITO?
AI: Of course Jc will depend on the temperature and magnetic field.
This paper...
Aliev, A. E., de Andrade, M. J., & Salamon, M. B. (2016). Paramagnetic
Meissner Effect in Electrochemically D... |
H: Tap into 12AWG wire with 20AWG wire
I am using 3 of these Mighty Max 12V 12Ah batteries on my Razor MX650 electric bike and they are connected with 12 gauge wire. I would like to tap into the power on one of the batteries with a 20 gauge wire. Is it ok for me to tap into the 12 gauge wire with a 20 gauge wire to pu... |
H: Can we consider an XNOR operation as an even number of 0 checker?
I am a little confused about the role of XNOR operation when we have more that two inputs.
After simulation, I realized that when we use multiple two inputs XNOR gates, the resulted output is 1 if there is an even number of 0 at the inputs. I searche... |
H: Circle with arrow symbol interpretation in circuit
I am trying to find all currents in this circuit:
(Question 19 from https://www.allaboutcircuits.com/worksheets/algebraic-equation-manipulation-for-electric-circuits/)
Although I'm familiar with Ohm's law and can find values in series-parallel circuits, I don't kn... |
H: Routing USB 3.x Type-C Signals
I'm designing an open source USB Type-C Switch (KVM Style), and I started to route the USB 3.x SuperSpeed+ and USB 2.x HighSpeed differential signal pairs on the PCB.
The switch will have 2 input + 1 output USB Type-C ports. The USB 3.x SuperSpeed+ signal are switched by two ON Semi F... |
H: Tact switches only work once
I am trying to do a digital clock using an Atmega8A, LCD display (2x16) and four tact switches.
Key number 1 is connected to pin PD2, number 2 to PD3, number 3 to PB6, number 4 to PB7.
When you press key 1 you can choose between hours, minutes, seconds, when you click key 2 you incremen... |
H: Find the voltage Vab and current of the circuit I
I was asked to find the voltage Vab and the current of the circuit I.
I tried finding the voltage in ab using voltage divider, but I have two voltage sources and I don't know how to make the respective formula
A voltage divider is E*(R1/R1+R2) for the respective ... |
H: Is this an Inductor, mystery component 600R/2A?
I was checking a schematic for work, and I saw this component that I don't recognize, marked 600R/2A.
Since they are marked L and are used in combination with capacitors, I think they are inductors meant to serve as low pass filters in combination with the capacitors.... |
H: Raspberry Pi relay on GPIO does not toggle, but does on +3V power
I am trying to toggle an SRD-03VDC-SL-C (3V rated) relay with a Raspberry Pi GPIO.
When I put a wire to the Raspberry Pi 2B ground pin and the other to a 3.3V power pin the relay works (it clicks). I measured 3.28V with my multimeter.
Now, as the rel... |
H: Logic analyser reads bits as if they are shifted left by 1 bit, what could be the issue?
The logic analyser is from Hobby Electronics, and is being run on the PulseView software.
It is not reading the data correctly. All of the bits are shifted one to the left so everything is read incorrectly.
I tried changing the... |
H: Why does wiring to a surge protective device need to avoid sharp bends?
Here is an excerpt from some Schneider Electric installation instructions for their QO2175SB 240V single phase "SurgeBreaker" SPD:
NOTE: The SPD ... must be
installed as close to neutral assembly and main circuit breaker or
main lugs as possib... |
H: Why use const variables instead of preprocessor directives when programming embedded with C++
I read on here that when programming with C++, const variables are better than preprocessor directives, ie #define, for declaring constants. I'm confused about why that is the case.
I understand that a const variable would... |
H: Help with possible errors on LM306 datasheet circuit diagram
Not sure if this diagram has some errors like missing nodes at wire crossing. There is an obvious one at a T-intersection but also I circled in red a couple other locations where nodes might be missing. One is below R9 because no output comes off the coll... |
H: Multiple Resonances along a transmission line
in "Lessons in Electric Circuits", VOL III, ChPT 14, all the possible configurations of standing wave for a certain transmission line are shown. For instance, this is the case of a transmission line left open at the ends:
According to the operating frequency and the tr... |
H: Subcircuit identification - Power amp
Could you please tell me what is the purpose of this highlighted part of the circuit? This is from a Soundtech 6150 powered audio mixer.
This specific mixer is outputting the supply voltage and has already burnt a speaker. The transistor on the top-right side of the highlighted... |
H: JFET as an amplifier
I'm working on this circuit below:
What is the functionality of R2 here? Stabilizing the input voltage? (If it was, it would've been connected in series, right?)
AI: What is the functionality of R2 here
It's used to bias the gate to 0 volts. Because an N channel JFET works with a range of neg... |
H: About 'water soluble solder'
I'm a hobbyist with a few years of practice and managed to make some nice musical instruments for myself, making steady progress over time.
For about the last six weeks, nothing I try to do works. Voltages are all over the place, I'm about to go mad. I'm even unable to replicate circuit... |
H: Disable stepper driver
I'm trying to disable the stepper driver to allow manual operation of the lead screw it's controlling.
I've tried connecting MF+ and MF- to ground and 24V in multiple combinations but the motor was still energized. Any ideas? Thank you.
AI: How are you driving the other +/- inputs? Drive MF t... |
H: How can I calculate the dead time to prevent shoot-through?
From Figure 1 is evident that to get the dead time I must define the values for RC. E.g my resistor is 220 ohms and capacitor is 0.1uF this gives me 22us at 1-time constant, however, when I measure this on my Pico scope this shows roughly 6.5us at the poin... |
H: How does this overvoltage protection work?
I was looking around for low cost and effective overvoltage protection, and I found this from this page:
With this part list:
RXE025 - 250 mA PTC resettable fuse
Zener diode – 5V6, 1 watt
Resistor – 1K ohm, 1 watt
Transistor – BD139 (NPN medium power 80V, 1.5A CC rating)... |
H: DC Circuit Analysis from Sergio Franco Book : Electric Circuit Fundamentals
If current source is absorbing power then the polarity wise Vb will be +ve.Then i calculated the value of Vb=4 x 2A = 8V
Va= Vb + (20*2) = 48V
and Vs = 164V
Thus for current source to absorb power of 0 W., voltage source has to change fro... |
H: Controlling a power supply with a MOSFET
I'm making a circuit that will have a main part (up to 5A load) in a back box, mostly unreachable, and a control panel at the front.
I want to have a kill switch at the front panel, so that I won't have to reach for the back part, but I don't want to bring the main load wire... |
H: C++ AVR big code size & excess unused symbols in build file
I'm developing the program for the AVR microcontroller in C++.
I have created a class that contains 8 methods(with constructors) but used only 3.
Class code:
class Pin {
Pin();
Pin(PinId pin_id);
Pin(Port port, uint8_t pin);
void SetDirect... |
H: time domain reflectometry on long cables
Is it possible to use time domain reflectometry on cables with a length of more than 100km?
What kind of problems do time domain reflectometers on that long cables face?
AI: If I have done my math correctly, in the region where the characteristic impedance is relatively cons... |
H: Separately excited DC generator as a constant current source
Is it possible to operate separately excited DC generator as a constant current source using the following method?
Keeping torque due to prime mover and field winding constant, reduce armature reaction close to zero using compensating windings and interpo... |
H: Fourier coefficient and resolution in simulators
I post below two fourier graphs of the same signal, simulated for two different transient durations:
The time domain function is a sine with 60Hz frequency.
Transient duration 40ms gives the following fourier graph:
Transient duration of 300ms gives the following... |
H: How can such an equation for the temperature of a *black body* be valid in this case?
I am currently studying The Art of Electronics, third edition, by Horowitz and Hill. Exercise 1.6 says the following:
C. Power in resistors
The power dissipated by a resistor (or any other device) is \$P = IV\$. Using Ohm’s law, ... |
H: SPI protocol implementation and delay
From my understanding, SPI is implemented by using 2 shift registers, one at each device.
Shift registers are a serially connection of D-flipflops
If the same clock is used to transfer data from master to slave and from slave to master
If the clock signal is clocked at MSB on t... |
H: Motor rewinding - saturation concerns
After reading a lot about 3 phase BLDC motors there's one concern that's nowhere to be found.
Let's say that we have a 1000 Kv motor and we want to rewind it to 10 Kv to get unrealistically high torque at low RPM. And let's say that we have the right diameter replacement copper... |
H: Estimating VAC rating from VDC rating
I have encountered several terminals, sockets, cables, and similar components which are rated in either DC or AC voltage, but not both. I sometimes want to use an AC rated part with DC or vice versa. Is there a way to identify when this is obviously unsafe?
For example, I know ... |
H: RLC band pass filter — getting the correct phase
Consider the RLC band pass filter circuit:
I’m trying to construct this circuit with a maximum of the transfer curve at \$f=5-6\$kHz and bandwidth \$\beta=2\pi \cdot 2\$kHz and so I have chosen a 88k\$\Omega\$ resistor, 7H inductor and 0.1nF capacitor, according to ... |
H: 20 amp to a 40 amp circuit
On the back of my house is the breaker box. It has an open 40AMP fuse (not connected to anything any more). There is also a 20AMP fuse connected to my shed. When the shed was originally built, it was only going to be used to hold junk and so a couple of incandescent light bulbs worked fin... |
H: What is the meaning of over sampling EFR32FG14 ADC?
In chapter 28 the SAR ADC is described. It says that we can have 12-bit sample with 1 mega samples per second.
Assuming I have set the ADC to work that way, what is the meaning of oversampling it?
It cannot produce more samples than what we set it to be.
So ther... |
H: Unsigned int values gives negative number above the halfway point of max byte value?
MCU: Atemga328P: Datasheet:https://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-7810-Automotive-Microcontrollers-ATmega328P_Datasheet.pdf
Note: I am a beginner :)
Considering a 2 byte unsigned int data type, where 65535 is the ma... |
H: Flooding GND plane in the top side has any problems?
Hope Everyone is doing well.
I got confused in the grounding of PCB.
I checked many open hardware boards I noticed they don't flood GND plane in the top side to connect SMD components( all components on top ) which is appeared to me the best way to minimize the n... |
H: Why can't I make flip-flops in logic simulators?
I've been playing with a few logic simulators and don't understand why flip-flops are not working. I'm trying to implement a T flip-flop with NAND gates:
All the simulators I've tried give the same result. Either Q or Q' takes the state of the clock rather than togg... |
H: How does this expanded memory bus work?
I'm reverse engineering a laser printer (Laserjet 1320) and I need to infer some things about the memory bus. The full schematic I've made while reversing is here (in pdf) on Drive. I'm not all that familiar with embedded hardware memory mapping and this part confuses me:
Th... |
H: XTR115 current loop transmitter more steady output
I'm using a XTR115U in my circuit to make a 4-20mA output. As I found out this IC is a current amplifier based on the below image on the datasheet.
To test this IC, I connected the 2.5V Vref using a 20K resistor to pin2 (Iin). But I have a flicker on the output wi... |
H: How to find Vthreshold and K (or beta) in Pspice/Orcad
Regarding M2n7000 transistor in OrCAD, I want to find its Vthreshold and Beta (or k) by its edit PSpice model.
This is what I get :
And by Vthresh and Beta (or k ) I mean the parameters of this formula :
By the way, regarding This Thread
I know the formula f... |
H: Can you turn AC into DC through a Spark Gap?
Is it possible to convert AC to DC using a spark gap as the medium, if so, could you provide a diagram?
AI: Yes you can, but you'll need a very special spark gap:
This is a mercury arc rectifier, in other words an oldskool thyristor.
A real spark gap, like this one, is ... |
H: Flicker-free brightness control of RGB LEDs
I would like to individually control the brightness and colour of 100 RGB LEDs. I would like to do this with a fairly smooth current through each LED. I.E. I would not like to use the traditional PWM method, because that causes irritating flicker on the retina, and proble... |
H: ltspice, simulate negative resistance, avalanche effect
I found some nice circuits here as a pulse generators
http://cappels.org/dproj/simplest_LED_flasher/Simplest_LED_Flasher_Circuit.html
The author shows some scope pics and films from real world.. working.
But when simulated in LtSpice... does nothing :(((
Wh... |
H: How do you use an LED's log V/I curve to force an exponential current change in the LED for a linear voltage change?
The info needed to make log and exponential converters with silicon is widely available. The saturation current, intrinsic resistances, and the Ebers-Moll equation are sufficient. A few other numbers... |
H: MOSFET voltage is opposite from what I expect
I have this circuit on LTspice.
The voltage from the 12V seems to rise when the 5V is falling.
What am I doing wrong?
AI: This is what you should get.
If V1 is 0V M1 is turned off so R1 pulls the output up to 12V.
In this state imagine the circuit without M1 present all... |
H: Servo motor signal voltage vs "working" voltage
I'm looking at a few servo motors (on Amazon.)
Typically the "Working Voltage" is 6-7.4V. I can supply that with a power supply but what can I do about the signal? Can I just feed it the 5V PWM from an Arduino? Sadly there's no other voltage mentioned on the listing; ... |
H: How to calculate measurement error in a voltage divider?
I'm trying to calculate the measurement uncertainty of the voltage represented by the ADC in +/- V or % of a voltage measured across R2 of a voltage divider.
What would be the general way to tackle this problem? I found a video of someone calculating measurem... |
H: Inverting a Sine Signal
I created a sinusoid signal(red) using the 555 timer in LTSpice. My goal is to flip this signal about the time axis (i.e. 180 degree phase shift)s so I thought I could use an Op Amp inverting amplifier to do. The resulting waveform (yellow-green) is somewhat like an inverted sinusoid but not... |
H: Exchanging Li-ion batteries: what to take into account?
I am looking forward to exchange a swollen Chinese Li-ion battery with a 'normal' one.
The device had this one:
https://www.aliexpress.com/i/32908652788.html
and I am considering to exchange it with this one:
https://api-lemona.lt/TI/En/Pdf/accu-18650_spcb.pdf... |
H: Can a 3.3v logic i2c be directly connected to 5v logic i2c
So can a 3.3v mCu directly communicate via i2c to a 5v mCu ? the buss will be pulled to the lower voltage 3.3v. And since i2c protocols involves just sinking current is what makes me think it will work
AI: It depends what the \$V_{ih}\$ minimum level is on ... |
H: How many standard deviations is Sensor / Component Uncertainty (+/- X) given in?
For example a resistor of 1kohm with uncertainty of +/- 1%, does this mean in 68% of cases = 1 standard deviation, the resistance will vary by +/- 1%, or does it mean in 95% of cases = 2 standard deviations or is it in 99% of cases = 3... |
H: How to calculate current in this circuit?
update:
How do I calculate current in this circuit if switch close at t=0 and the circuit initial conditions are \$IL1(0)=2A\$?
AI: To answer the question you pose in your comment (changeing the circuit to include parallel resistors) - I would find whatever quantities I w... |
H: Non-inverting UA741 opamp simulation on QUCS
According with instructions provided here https://www.youtube.com/watch?v=dBY1k5qK2w4 (in Spanish), I tried to simulate an inverting opamp configuration, but I couldn't figure out the right vout behavior, as reported in the second graph of the following figure.
Output r... |
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