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H: Understanding a simple opto-isolator circuit
I have this circuit that is part of a schematic that I am trying to read.
I have some idea, but I am not sure that I am correct. All I want is to figure out the D0 and D0_3V3 values.
For example assuming that the circuit that is connected to left D0 is set to low (no vo... |
H: Physical operations of discrete - time circuits
I have a basic doubt about discrete time circuits.
A discrete - time signal is a sequence of values which are taken at specific time instants (let's call them sampling instants), as we can see from the following picture:
So, from what I have understood, a discrete - ... |
H: ULTRA X3 D0409 1000W PSU and high 3.3v rail voltage
I just got ULTRA X3 D0409 1000W PSU for a rig which I'm building and before putting it in, as always, I have it checked with PSU tester and came up that 3.3V rail voltage is going high (up to 4.1) but it will fluctuate after that between 3.7 and 4.0
I think going ... |
H: Signal velocity in PCB traces
On what does the signal velocity depend for a signal traveling through a PCB trace?
According to Wikipedia, it depends exclusively on the relative permittivity (ε_r) of the medium (well, it also depends on c, but that one is a constant), under the approximation that for PCBs, the relat... |
H: Is there a way to recycle/use negative half of AC voltage from a rectifier?
Forgive me, as I am far from an electrical engineer, but when rectifiers were explained to me I found that a rectifier allows current only in one direction, which allows it to filter out negative voltage of an AC power source and only outpu... |
H: Buck Converter Capacitor and Inductor Characteristics
I'm trying to make a buck converter with this mickey-mouse MC34063A chip that will step-down +5V to +3V3 up to 500 milliamps. I've gone through the calculations by hand and validated them with an online calculator as well. My PCB works great with small loads, bu... |
H: NUCLEO-STM32L432KC: How to use UART through USB?
Back with my STM32 adventures(data sheet). This time trying to get UART data through the USB. Essentially I want to be able to print over usb to start printing out variables to further debug code.
I am using the classic NUCLEO-L432KC board and I read somewhere for de... |
H: Resetting 555 via Transistor - RESET PIN LOW TOLERANCE
I have a circuit with a NE555DR timer that generates a pulse. The reset is held low and lifted when a voltage of 5 - 24V is applied to P0-3.
A PNP transistor MMBT5401 that pulls pin 4 to ground when inactive.
The Simulation is correct for the voltage at pin 4, ... |
H: Identify these potentiometers or variable capacitors
I recently came across an old radio that has these odd parts on them. They are labeled "T3" and so on, so maybe they're some kind of capacitor or transformer?
They're adjustable at the top and branded/stamped "JET" around the adjustment screw.
In the last picture... |
H: Soldering USB contacts - what kind of solder tip and what temp?
I am going to try and make my own mechanical USB cable. For soldering the wires to the usb plug, what is the recommended Solder tip type/size and also what is a good temp to use?
AI: I would use a fine tip, very thin.
Also some very thin solder. The ... |
H: Trigger Circuit
Whenever voltage goes above 19V , it should provide High signal (2.5V to 5V) to the G pin and rest of the time it provide Low signal (below 0.5V). The currently shown resistor divider solution will not work.
AI: You need an analog comparator to be able to set a precise switching threshold. |
H: Is this reason why we can let the current source be attached to a grounded?
In this question, someone shows me that these two circuit are equivalent. I want to make sure that my idea about why is these two circuits are equivalent, is correct.
The inner resistor of an ideal current source is infinity,and how much ... |
H: what is the load line and operating point used for in practical?
I have a hard time understanding what an operating point and load line represent and why do we need them at all.
After reading some wikibedia,
What I got is this load line represent response of the linear circuit attached to the diode for changing in... |
H: Suspending a Nichrome Heated Coil?
Scope:
The scope of this project is to repeatably light several fireworks simultaneously (Mandalorian Whistling Birds Vambrace build). This requires that the only action required to light more firework rockets would be to load them into the device. I have looked into the ways peo... |
H: Why do bare die chips (MOSFET) have a maximum storage temperature?
As far as I understand, a chip in general and a MOSFET in particular has a maximum operating temperature (let‘s say 125 °C or 150 °C for Si) because above that temperature the risk increases of building a thermal runaway that creates a positive feed... |
H: How to find out the values of a surface capacitor
Surface resistor has numbers on it to decide whether it's good or bad after measuring it with DMM.
But when I looked at surface capacitors, they don't have numbers or strips to decide their validity and to replace them with new ones with the same values (In case the... |
H: P-MOS Gate-Source Threshold Voltage drop (Along with inrush current limiter)
I am having a circuit which I have tried to simulate and understand the working.
Circuit parameters :
Zener Breakdown voltage = 6.2V
P-MOSFET Vgs threshold voltage = 1.5V
Inrush current limiter = 3.3ohms
Below are my simulation efforts :... |
H: How to find the phase of this transfer function?
I have been trying to find the phase of this transfer function:
G(jω)H(jω)=0.1695/jω(5.88jω+1)
by doing this:
Phase = -arctan(0/0.1695)-arctan(w/-5.88*w^2)
PHASE = 0-arctan(1/-5.88*w)
Is this correct ? since for some reason the result does not make sense.
AI: Since t... |
H: Reference voltage for a comparator
The question is to determine the reference voltage for the comparator shown in the figure below:
After I understood that by the reference voltage is meant the voltage at the negative terminal, then I came up with this solution:
The voltage drop at R1 should be 10 V and the voltag... |
H: What does 'passband phase' and 'stopband phase' mean?
I've been provided with a Bode plot for an RC filter circuit with a cutoff frequency of 10kHz. Im asked to find the stopband and passband phase from the graph. I'm confused how these can be just a single number, since stopband and passband represent a range of f... |
H: How do I decide on a proper PCB ground layout?
I'm trying to figure out best practices regarding ground layout, but it seems the more I read the less I understand about the subject as many recommendations seem to contradict themselves.
So far I am under the impression that when using a ground plane one should rout... |
H: Connect LED-driver (BJT) in circuit
I need some help in this circuit!
How can I connect LED-driver (BJT) in this circuit? Then what is the valus of RB and RC that meet the requirements, so that the LED driver works properly.
Hopefully get help
Online circuit: https://www.circuitlab.com/editor/#?id=f5rq8hvpj63d
A... |
H: Turn On Relay by Phone Line Power
I have two corded phone lines that I want to connect both of them to one telephone device. The phone must be connected to line 1 by default, and it switches to line 2 when it rings. I made a simple circuit to detect line 2 ring signal that turns on a 2-contact relay to switch lines... |
H: Working of a transistor in a TTL inverter circuit
I was referring to TTL inverter circuit in the book Digital fundamentals by Thomas Floyd and its working principles first proposition went as follows:
When input is HIGH, Base emitter of Q1 is reverse biased and base collector is forward biased.
This permits the ... |
H: Why to use signal in this VHDL code?
Here is my code for 4 to 1 mux:
entity a is
Port ( a : in STD_LOGIC;
b : in STD_LOGIC;
c : in STD_LOGIC;
d : in STD_LOGIC;
contr : in STD_LOGIC_VECTOR (1 downto 0);
z : out STD_LOGIC);
end a;
end a;
architecture Behavioral of a is
begi... |
H: How would a NOT gate be implemented by Josephson Junctions
I'm interested in learning how Josephson Junctions can be utilized to create invertible logic gates. To me it's not clear how the Junctions provide any logical capability (they simply allow for a current flow across an insulating channel but lack any switch... |
H: Help deriving a 2-port representation of an RC filter circuit?
I have the circuit below. Its a basic RC filter circuit with source impedance 50Ω from a signal generator, and load impedance 1MΩ||20pF from an oscilloscope at the output. The input voltage V2 is a 10kHz sine wave with 10V amplitude.
I need to derive a... |
H: Efficiently driving 6 LEDs in parallel
I have a display that has six white LEDs in parallel (common anode) as backlight.
The LEDs' forward voltage is 3.2V, the current per LED is 20mA, so 120mA in total.
The available voltages in the circuit are 3.3V and 5V.
Of course I could use 5V and a serial resistor for every ... |
H: 12V lead acid battery instead of 11.1V LiPo?
I'm doing research on a remote control model ship. I have 11.1V LiPo batteries, but because of their weight and duration, larger batteries are considered better in this application (these batteries come were originally for RC airplanes, where lightness is key.)
My batter... |
H: Why do my tests pass using a "wrong" JK flip-flop model?
I have a testbench written for a JK flip-flop. Below I have the correct circuit that passes the testbench and another circuit which passes the testbench as well. Is there something wrong with my testbench?
a) Correct JK flip-flop:
module jk_ff (input j, input... |
H: Why does my ungrounded DC power supply work?
This is a question about electronics theory that I haven't been able to grasp. I was testing a stepper motor wired like the following: https://learn.adafruit.com/adafruit-tb6612-h-bridge-dc-stepper-motor-driver-breakout/using-stepper-motors
The only difference was that i... |
H: How to calculate the PI model equivalent transformer parameters
I have a power transformer with the transformer ratio 200kV/100kV, 100MVA rated power, and specified R = 0.001 p.u., X = 0.05 p.u. For a calculation I have to make, the literature I am using is referring to the "PI" model of the transformer:
How do I ... |
H: Understanding the application of a switching regulator as a constant current LED driver
There is an application note from ON-semiconductors which provides a few diagrams to use a well known MC34063 switching regulator as LED driver. it's around the idea of setting the 1.25v feedback value using the voltage drop of ... |
H: Current transformer with additional multi-turn winding for test purposes
Some explanations for the circuit below:
This is a CT with 1000 turns secondary. It has high sensitivity
down to mA levels so that's why I put an amplifier given that the
burden is small (35 ohms).
The CT has 1000 additional turns for the tes... |
H: How to Prevent CD4017 from Resetting to Random Count on Power On
I'm working on a project using a couple of CD4017 decade counter chips sharing a clock signal from a 555 oscillator.
The ideal behavior I would expect is that the chips would all start on count 0 when given power. They do this most of the time but so... |
H: How do I attach leads to a SOT-227B/miniBLOC package?
I am reviewing options for full-wave rectifiers for a several thousand watt project, and many of the options are in the SOT-227B/miniBLOC package. I am not familiar with this package, and when I was reviewing its mounting guidelines, it was unclear how external... |
H: Are only standard footprints ever used? What if a manufacturer wants a devices footprint but the manufacturer doesn't list it?
They want a BOM like this but the part I want doesn't list a footprint. It lists the components dimensions and then you have to make the footprint yourself so I don't think there is a stand... |
H: High pitch audio frequency measuring
Wondering on how could higher pitches than 23 kHz be measured, I can only find devices measuring to about 21kHz.
Main question is: how could audio frequencies about 26 kHz or 30 kHz be measured, on dBFS and frequency; ones on my smartphones, television and woofer only reach 21 k... |
H: How we got exponent as \$2^{127-64}\$?
Information: Consider a 16-bit register of the following format is used to store a floating point number. Mantissa (M) is denoted as normalized signed magnitude fraction, Exponent (E) is expressed in excess-64 form. Base of the system is 2.
If we calculate then, we get, expon... |
H: How to build a complet circuit with the following led in left and the following circuit in the right?
How to build a complet circuit with the following led in left and the following circuit in the right?
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AI: This circuit is a driver for the LED. The transistor will be working in the saturation region to turn on... |
H: diodes selection for MOSFET protection against inductive load
Hello I would like to design protection for my N and P channel MOSFETS against inductive load. According to this article, Their IC is best but it cannot hanndle my application so i have to use the next best which is to use a TVS setup as to only a free w... |
H: Battery charger vs Voltage or neither - They offer accurate power consumption? (mA)
I want to measure the power consumption not in theory but in time (after one day of use).
I don't have equipment to measure the power consumption but I have a battery charger that reports mA charged and "arduino" devices that report... |
H: Calculate capacitance value and voltage rating in the event of ESD pulses
I have a input power filter circuit.
It has ESD protection capacitors which help to protect the downstream circuit from ESD pulses.
ESD Capacitors Specifications :
C0001, C0002, C0003, C0004 = 47nF, 100V, 10%, 0805
My ESD Pulse Specification... |
H: Dali - Handling multiple responses
I have found a similar answer related to taking care of multiple responses in a Dali bus system:
DALI: Handling multiple responses from DALI system
I'm designing the dali control device(master). I have finished the commissioning process and now testing it with 2 control gears. It... |
H: Truncation noise in digital circuits
I was reading a chapter of my book (I am not putting it as reference since it is not in english) about the quantization noise problem in digital filters. Specifically, it writes about a filter that performs multiplication operations:
"If the input, the output and the multiplica... |
H: Help convert this charging indicator circuit
I have found this schematic to track when a battery is being charged, but I don't know how to convert it to work with a different voltage.
The charging voltage is 25.2V and the lowest the battery can go is 22.2V. I want to charge it with up to 2 amps.
I am not very good ... |
H: Thevenin Equivalence Problem
So I have this question that I'm struggling to understand and solve, it goes like this:
I want to determine the Thevenin equivalent of my car battery. You measure a voltage of 12.2V across the battery while it supplies a current of 1A. When I turn the headlights on, the load current inc... |
H: Voltage Regulator giving wrong output
I'm attempting to fix my desktop motherboard which is damaged by power surge, and I noticed that the +3.3VSB is giving 1.6 volts. There are few voltage regulators around the board, I checked them either and they're working correctly (Convert from 5v to 3.3v). I tried replacing ... |
H: Charge pumps operation
In a course of digital electronics, our Professor wanted to give us just an introduction to charge pumps.
Here the basic topology:
Then he says that the circuit behaves like a bucket brigade chain: a charge packet is transferred by Vdd to CP1 (when CK' is high), then from CP1 to CP2 (when CK... |
H: How to remove excess top silk in Proteus?
I have some markings on my plate made in silk and I believe they can hinder the welding, since a line is passing inside my pads, I know that when a silk line passes over the track there are no problems, but if a line passes over a pad and its welding mask? Wouldn't that be ... |
H: I'm trying to find the the voltage across the capacitor before and after closing the switch and graph the response
This is the initial circuit
After some simplification the circuit changed into this
Then for solving the for the switch open I simplified even further
So For t=-0 -> ic(0)=0
Using mesh current anal... |
H: Offset and scale a DAC output with opamps
I am trying to make a simple oscillator controller with an arduino and a DAC, to learn electronics.
I need to send a voltage between 12V and 17V to my oscillator to control its frequency. I got a 24V power and a 12V ref voltage. My DAC produce a 0/5V voltage.
I made a reall... |
H: What sample rate do I need to analyze usb 2 with a analyzer?
What is the sample rate needed for a logic analyzer to be able to analyze a 480 Mbps USB 2 bus?
AI: Nyquist basically says you need at least double the bandwidth (aka the highest frequency component of interest) in your signal to get a sampled waveform un... |
H: Why is the oscilloscope in Multisim software showing more voltage than the source?
The Multisim oscilloscope shows around 13V peak despite the voltage source being 12V peak. I was expecting 12V. The diode voltage drop is set to 0.1v when forward biased.
Am I missing something?
AI: See the green circles I've adde... |
H: Decoupling capacitor for digital potentiometer
I'm designing a circuit that contains an AD5206 digital potentiometer. I'm using a single 5V supply and the IC has both GND and VDD pins tied to ground.
The data sheet does not make any recommendations for decoupling capacitors and specifies a maximum current draw of o... |
H: What could be the reason an ATX PSU triggers OVP?
I have a broken MARS MP600 PSU that I am trying to repair.
Everything looks good but when I turn it on (grounding PS_ON) the outputs do not maintain the voltage.
The output signals go to the rated voltage, start increasing softly and then everything turns off, this ... |
H: Where am I wrong? I think my calculation should be correct, but my answer is wrong
The question wants me to calculate the \$V_3\$ value,and the solution is as below.
Solution:
\$V_3=(\frac{10}{2}+5)(2//3)=12V\$
simulate this circuit – Schematic created using CircuitLab
However, here is my thinking. My answer is no... |
H: Help in choosing correct power supply for LED matrix
I'm quite new to electricity and electric components. I'm building an LED matrix from scratch on a small PCB. I will be using an IC for multiplexing, Transistor for controlling external power supply besides Arduino, resistors and of course the LEDs.
Now, my gener... |
H: PCB female jack and power supply male melted
I've been working in my thesis project which consist on a PID controler to mantain a certain temperature in a case. The heater module is made of two 40W-12V 3D printer resistors and one 15W-10 Ohm wirewound resistor. In addition to these, I have an Arduino Uno, a 20x4 LC... |
H: Need to identify cable
Would need to identify this cable for a replacements:
Codes:
PF000624.02
KW 1947 38
Data Matrix Code: 1STHGCW0020P42
Pins: 15
The cable is from DJI Mavic Mini controller (CE version) ant it connects the main board with contoller buttons.
AI: That's a custom flex PCB, so you can't buy it fro... |
H: Snubber circuit to protect SCR/Diode
In my circuit I need to discharge a capacitor into an inductive load using SCR. In order to make the circuit oscillate there'll be a diode antiparallel with the SCR, as you can see in the picture.
My plan is to let the circuit oscillate only one sine wave cycle and then stop (I... |
H: Find base resistance value
I need to choose a value for R1 to get the bulb shining. I was aiming to deliver 2 A current in there.
In the circuit below I am using NPN BJT transistor with beta value of 100 and built-in B-C potential value of 0.7 V.
My approach to figuring the resistance is
$$I_b=\frac{I_c}{\beta}=0.0... |
H: Does voltage drop limit the maximum current that can be draw?
I'm a newbie to this area. I'm having a few questions about the ohm law.
The given scenario is, In the circuit, there is a power source of 5V, and a resistor of 1 ohm. This means there will be 5A current come through the resistor, so the voltage drop is ... |
H: How to boost a Power Bank's maximum output voltage?
I have an Anker ~27Ah Power Bank which has 3 × (5v , 3A) power output.
Is it possible to connect the outputs in series and get 10v or 15v output with a current flow of 3A?
AI: All the 5 V outputs share the same ground hence they cannot be connected in series. To ... |
H: USB to ethernet chips like LAN7850 require GPIO to RESET pin?
I am designing a PCB which uses LAN7850 chip
This is the first time I'm using such a chip and I'm very newbie to PCB designing.
Please advise if this Chip requires a GPIO pin from the microcontroller to control the RESET_N as I have done in this image.
... |
H: Calculate time it takes for a capacitor to discharge, when it is applied to VGS of a transitor
I want to usea 1uF capacitor to create an electric field between Gate and Source (VGS applied to dielectric) of a transitor.
simulate this circuit – Schematic created using CircuitLab
Since no current is flowing can i a... |
H: What is this symbol that looks like a 3/4 circle connected to wires?
I am reading an application guide related to high-voltage DC and have come across a symbol that I do not recognize:
The source of the schematic is this document from Siemens.
Based on the context, my guess is that it might be either some sort of ... |
H: Driving Logic Level NMOS and PMOS
I have always this mindset that to drive a MOSFET you have to apply a certain voltage to the gate of the mosfet to turn it "on" But it would seem that it not entirely true, you have to apply a certain voltage into the gate with reference to the source pin not necessarily the ground... |
H: FM broadcasting text
I was listening to a local FM station from my smartphone using a headset.
While I was surfing over the available bands I saw that few FM stations can broadcast the name of the song/music details (song name, movie, release year) while playing.
While a few stations broadcast their FM brand name... |
H: Why the voltage across MOSFET (VDS) is increasing even when the voltage at the gate (VGS) is constant?
Following is the screenshot schematic for Buck-derived half-bridge isolated DC-DC converter in LTSpice.
In the following plot it can be seen that when the lower switch is turned off the voltage across it (purple)... |
H: how to initialize wifi settings in a production IOT device
I want to build an IOT product that logs/polls values from a server. The problem is that all of the arduino/esp8266 and similar modules that I have found require the user to initialize the device with a wifi username/password. If I want to sell this device ... |
H: Inrush current of high voltage power supply
I have seen some solutions for inrush current, but my case I think it's a little different.
The point is that I need to limit the inrush current of 1500 volts peak rectified. In my project I need to keep charging and discharging a 200uF capacitor with 1500V every 50ms. So... |
H: AC-AC Converter 3 phase, Line to line voltage calculation
I’m working one some assignment like this circuit (AC-AC converter 3 phase, 89 degree firing period). I've done this on PSIM software with 110 Volts 3 phase voltage source.
I've been told to analyze the line to line voltage. The waveform and the value looks... |
H: How to test if a capacitor is good if my DMM farad's range is less than the capacitor's
So I found out that my DMM maximum reading is 100uF (Though its price is twice the ones that reads upto 100mF, mostly because its 8 years old). It doesn't have manual range for capacitance measurement, it's auto range (From 50nF... |
H: What is the purpose of clamping the gate and source of a mosfet
Is clamping the gate and source of a MOSFET really important? I have seen this in some articles and some datasheets of MOSFETs where they have built in clamping.
As far as i know they are used for ESD. Asuming that the gate is just a trace to a contr... |
H: Current wave form of an inductor
If this voltage is applied to an ideal inductor. How will be the current waveform look like?
Kindly any one show me the graph for inductor current and if possible explain it. I shall be very grateful! (Voltage is in blue)
AI: Kindly any one show me the graph for inductor current and... |
H: Mosfet controlled LED strip not bright enough
So, I'm trying to control a LED strip with a NodeMCU using N-MOSFETs FQP30N06L, one for each channel. However, the strip is not nearly as bright as with the original IR controller. (I saw the similar question, however my transistors are definitely logic-level)
The main ... |
H: Can you power a 3.3 led with an arduino 5v output?
I have a led that can handle 10 milliamps at 3.3v. Can I use a voltage divider and a plus resistor to power it from an arduino nano 5v digital pin?
Maybe something like this.
simulate this circuit – Schematic created using CircuitLab
AI: 5 volts needs to reduce t... |
H: Audio Capacitors - NP0/C0G or Film in Loud Enviornments
I hear a lot of "audio-foolery" going around about capacitors and I have always steered clear of multiplayer ceramic caps because I was under the impression that they are microphonic.
I am designing a circuit that will be used in a club environment, eg 100dB ... |
H: How a blue LED works and how this affects how the LED driver is set up?
How a blue LED works and how this affects how the LED driver is set up?
Is Someone here have a good explaination?
AI: Practically all LEDs work on the principle of injection electroluminescence which is the process where light is emitted as the... |
H: Single supply opamp with AC coupling
I am trying to make an amplifier with an opamp, using a single supply.
I found lots of ressources online. This response was very informative and I tried to simulate this circuit.
Let's say that I have +/-0.5V signal, and I want to amplify to +/-1V. This is what I did:
(simulati... |
H: Times a DC motor can be driven from pair of AAA 1000mAh
If I have 3V voltage made from two AAA in series, both 1000mAh and driving a 3V 1.5W DC motor with it, being the duration of tON exactly 1 second for each drive attempt. Is it possible to estimate the quantity of times the motor will trigger until the end of t... |
H: Unable to communicate with LCD2004a via I2C (Nucleo-F103RB)
Hell guys, i'm trying to communicate with LCD2004a with the I2C extender.
i followed this guide: https://www.youtube.com/watch?v=7mQppaEJjT4
what i did:
I generated project using CUBEMX to Keil uvision
configure I2C with those parameters: 100Khz CLK, slav... |
H: Can anyone tell me why can the author just write the formula of Thevenin equivalent voltage of this circuit?
How to find the thevenin equivalent resistance and voltage?
simulate this circuit – Schematic created using CircuitLab
The solution for calculating the thevenin resistance is
\$(5//20)+2+1+2=9\$,i can unde... |
H: Why is "GaN tech" so revolutionary for wall chargers?
A big selling point of RAVPower wall chargers is that they use "GaN tech."
I assume that's gallium nitride but, anyway, my question is: If that's what their chargers use what do most other wall chargers use? Silicon?
How do they use it?
This picture from the ... |
H: Is it safe to connect lithium protection circuit to positive terminal of the battery?
I'm designing a lithium battery powered circuit, and want to include a battery protection circuit (e.g. DW01, but the question is applicable to other chips as well). All example circuits I can find on the internet place the contro... |
H: How a battery is being charged and used as the same time?
this is very interesting question to me that why batteries can be charged while being used as the same time? I designed a buck converter that charges a battery from a solar panel but and when I want to use the battery I would enable a relay that will cut the... |
H: What is pinched off current?
I know what pinch off voltage is.It is the gate-source voltage at which drain current is cut off completely (pinched off) is called the pinch-off voltage.
But what is pinched off current?
AI: For any particular gate-source bias voltage, when the drain-source voltage reaches a certain va... |
H: Biasing the push-pull follower to eliminate distortion
Could anyone please explain me the circuit? Especially the role of the 100 ohm resistor. In addition, which of the transistors conducts in positive and negative input? Thank you.
AI: A BJT does not begin to conduct until the base-emitter voltage reaches somewhe... |
H: Sensing solenoid current
I want to sense the current through a solenoid when it is ON. Ideally I would want this for testing purposes and overcurrent protection. As I have a free ADC pin in my microcontroller, I came up with the approach below. I don't expect a current greater than 500 mA, and the coil will be give... |
H: Did I build this AC-coupled emitter follower correctly?
Some connections seem to lead nowhere on the diagram...
AI: It's an amplifier circuit. That means it has an input and an output.
Input is on the left and output is on the right. This is the conventional way to draw schematics, signal flow from left to righ... |
H: ORCAD - Oscillator startup
I'm simulating an oscillator that I have designed for a 40kHz oscillation frequency. I simulated it in Orcad and I got a flat signal. After some research, I found that it's due to the program not calculating any noise or something to start the circuit.
I added an Ipulse to simulate nois... |
H: Triac's gate isn't fully activated
I'm testing on BCR12LM-14LB8XO Triac. According to its datasheet, the gate is triggered by a 1.5v.
https://alltransistors.com/scr/datasheet.php?pdf=BCR12LM-14LB
I have a 2.7VDC power source, 700mA maximum.
I'm testing the Triac while it's attached to its electric board.
On my brea... |
H: Dual OP AMP setup circuit supposed to pull 2mA, but where is the other 4mA going?
This circuit uses half of the TI dual OPA2626 (not showing the other half of the OP AMP). This dual OP AMP supposed to use 2mA, but it's pulling around 6.8mA (measured at the Grnd pin and also at the Vcc pin). The other half of the O... |
H: What is this add-on to my 1980s AC magnetic contactor?
I'm renovating a Shizuoka ST-N CNC knee mill with a Bandit 3 controller from ~1980 in it. The spindle drive is a Todai Electric Co DC Motor Control Pack model number MOP-1500 which has absolutely no documentation online.
There are two Fuji Electric SRC3631-5-1 ... |
H: Will high inrush current (30A/115V) trip a circuit breaker?
I was going through some power supplies for my LED Lighting project and found an inrush current of 30A/115V in the datasheet. My questions are:
Will it trip my home circuit breaker?
How long does the inrush current last?
What does cold start mean in power ... |
H: Assumptions in the Calculation of Noise Vrms
I was doing some reading on noise analysis and its calculations.
The SRS lock in amplifier specifies input noise levels only at a certain frequency and not the entire spectrum itself.
For example: \$ 6 nV \backslash \sqrt{Hz}\$ at 1kHz,
But with such data, I can onl... |
H: Ohm's law and the voltage drop across a resistor
I'm trying to wrap my head around Ohm's law and there are plenty of similar questions already asked in this forum. But I just still don't understand it. It's about calculating resistor values.
Let's say that I have an IC which has an input pin I want to control high... |
H: How to find out which side of transformer the OC and SC tests were performed?
I have this problem which states that in a single phase transformer 2200/110 50kVA No load and short circuit specifications are like below, How to find out which side of transformer were the tests performed(I believe it means that the tes... |
H: emitter follower biased by input signal?
For the standard emitter follower you typically need input coupling capacitors and a DC bias of roughly half the supply voltage however what if the input signal itself swings around half the supply voltage?
e.g if the previous stage to an emitter follower is a standard op a... |
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