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H: Why does 3-to-5 volt with transistor not work the way it should?
A quick google for "3v to 5v transistor" gives me dozens of circuit diagrams that look like option A below with a NPN transistor and a pull-up resistor. If I build the diagram in iCircult, it works as expected. However, when I wire it up on a breadboa... |
H: Analog Multiplexer
In what ways can an analog multiplexer i.c fail? I want to use this in our system ,so i need the complete details of it,so that even if the mux fails,the output should connect to one of the input signals. Is this possible?
AI: It's likely not possible. The most common failure modes for ICs in my ... |
H: Working of a current mirror as an active load
Ordinary resistor as load in a transistor amplifier has a certain short coming…we cant have voltage and current gain simultaneously …..
In this circuit a current mirror is actings as an active load in place of RL …I wonder how this current mirror able to give voltage as... |
H: Dipole antenna VS. coil for RF transmission or recieving
Correct me if I am wrong, but all RF light waves are created via a changing electric and magnetic field. But when looking at all kinds of radios and RF circuits, this light wave is always made with a simple wire antenna. Why are coils not used instead? Wouldn... |
H: Is this true: "At over 700 Hz, current simply flows over your body"?
I have heard this in a movie clip. I was just curious to know, is this really true?
Because the one thing that I do know, is that at a high voltage, the current decreases, so that it doesn't harm a human body.
AI: Skin Depth
The human body does ha... |
H: What's this substance looking like glass cloth in an electrolytic cap?
This epic image of a blown electrolytic cap is from this question.
It looks like the cap is made of something that looks like glass fiber cloth inside.
What is that material that the inside of the cap is made of?
AI: It's paper or something muc... |
H: Is there a correct way to document RoHS compliance?
I work for a small electrical engineering company. Our products are not presently RoHS, but we're planning to switch over. As best I can tell, this is a matter of ensuring that our individual components are RoHS, and using lead-free solder. But what documents do w... |
H: Aux and Microphone to same input
I have a loudspeaker for my car and I've added an aux cord to the system so that I can play music over it. There is also a microphone attached to it and what I've done is add a 3 way switch between the two so I can either use the microphone or the aux cable. I don't really like this... |
H: What makes an arbitrary waveform generator arbitrary?
Why are some signal or waveform generators called "Arbitrary Waveform Generators"? Am I misunderstanding the word arbitrary? This question is not necessarily about the word arbitrary but more about arbitrary signals.
How is a arbitrary waveform generator differ... |
H: How to convert 10K Pot raw output ADC data to voltage and resistance from arduino uno?
I have a simple and basic question. I am using Arduino uno to read the output from a 10K potentiometer. I understand that Uno uses a 10 bit ADC, therefore it can display outputs from 0 as 0V to 1024 as 5V.
Question: I am getting ... |
H: Why PNP transistor might be opened even though (almost) nothing is connected to the base?
I have a simple printed circuit board with simple circuit on it. Very beginner. No SMD.
As a part of this circuit I have transistor BC557.
If I don't solder the base pin of this transistor and test the circuit then transistor ... |
H: Please explain FFT Frequency Spectrum and different filters
It seems that I am not able to find the right key-words in order to get the answers from google but how can I recognize different filters based on their FFT Frequency Spectrum and how do different filter look like in their FFT Frequency Spectrum?
I underst... |
H: Controlling an electric water heater
I'm trying to control the temperature of water heated electrically.
On devices sold commercially I see that temperature is not being controlled, and the heating elements are either turned on or off (based on the feedback from some thermostats), probably because it is expected th... |
H: How serial resistors actually reduce EMI?
I am recently working with a GSM based system, and there was this advice in the datasheet of the GSM module:
22 Ω resistors should be connected in series between the module and
the SIM card so as to suppress the EMI spurious transmission and
enhance the ESD protection.... |
H: Why would MOSFET transistor heat up?
I had a circuit on PCB. I used solder with acid-core to solder it. This combined with my mess soldering caused various shorts between components.
One of those components was MOSFET transistor BUZ11 which due to shorts heated up to the point of slight discoloring of radiator and ... |
H: Phasor diagrams for RLC series circuit?
So, here's the circuit:
How can I make phasor diagrams for the circuit in case when $$I_C<I_L$$ and $$I_C>I_L$$
Edit: What made me confused is the current conditions, it's actually voltage $$U_C<U_L$$ and $$U_C>U_L$$
AI: What @EMFields said is correct, i think you are gettin... |
H: Current Shunt Vs Current Clamp Meter - 15% difference Which one is right?
I have a variable AC power supply. 0-12V 0-1800A 60hz.
I have always been told to trust the current shunts and not current clamps when measuring current. The current clamps are supposed to accurate to less then 2%. Our current clamps have alw... |
H: Increasing Frequency of a Signal
I was wondering if it would be possible to increase the frequency of a signal by a fixed amount. Basically, I have a negative wire soldered to a speaker and a positive wire that very quickly breaks/unbreaks the circuit. As expected, this causes the speaker to pulse each time the pos... |
H: How can one verify if the FCC/CE certification mark on an electronic component or product is genuine?
Some companies can be unscrupulous and simply paste a label to fake FCC CE. How can one be sure the label is real?
Is there a website for checking the validity of the FCC CE mark?
AI: Search the FCC database by the... |
H: 2 NPN Transistor Square Wave Oscillator?
I have built the circuit found here.
I substituted with 22K resistors at R2 and R3, and substituted C1 and C2 with .022uF capacitors. These are all the components I have lying around. Everything else is the same. Even the transistor part number.
I realize that these substi... |
H: LTSpice capacitor ciruit behaviour doubt?
I have basic knowledge of electronics and i have been using LTSpice to clear my concepts lately. I also have breadboard, multimeter etc.
The first circuit i tested is a simple capacitor resistor circuit...
Below is the second circuit....
What confuses me is how in the fi... |
H: Find the power at the output of a random input + noise?
Problems on Linear Systems with Random Inputs
In this problem I don't know how to start.
the answer might be long. so it would be really helpful if you help me with the concept and the idea how to start
AI: Point A is quite straightforward.
To achieve \$\te... |
H: Close loop circuit vs an open one in regards to an electrical bicycle light system
From what I know about DC current, for it to flow you need 2 points with different voltage (while AC doesn't flow from point to point), this why DC batteries discharge overtime, when not used, because they are surrounded with a 0V en... |
H: Question on DC analysis of BJT - Common Base
I'm trying to solve a question from my book. The answer for the question is given but I keep getting a different answer. I don't know if I'm doing it the wrong way or the book is wrong.
This is the question:
This is my working:
The answer is apparently 0.921mA but I g... |
H: Do If else have priority in verilog?
I have some query about the priority of if else in verilog.
For example.
If (a)
b
else if c
d
else if e
f
else
g
At here, those a,b,c...g are all searched ?
How do those have priorities in if~else in verilog?
AI: An if-else construct infers a priority routing n... |
H: How can I objectively compare TCXO performance?
I would like to evaluate an alternate TCXO used in a GPS receiver circuit. Our current TCXO works good but I'm looking to test a lower cost alternate.
The alternate part is Epson TG - 5035CJ / CG / CE (datasheet).
Import specifications like voltage, frequency toleranc... |
H: PIC microcontroller DAC output incorrect
Using a PIC16F1825 microcontroller I was seeing incorrect values being output on the DACOUT pin. The setup stipulated using the fraction 8/32 * VREF+ where VREF+ was an external 2.5V reference. The output should have been 0.625 but was twice that value.
(have answer myself)
... |
H: Control Engineering: Model parameter estimation for a motor which will be under various loads
I am creating a closed loop controller for a motor which is part of a robotic arm. I give it a required angle, the controller calculates a control input, the motor moves, a pot feedbacks the angle, repeat, and the arm ends... |
H: 64k x 8 RAM - what exactly does it mean?
I'm looking at this microcontroller because it has the protocols that I want and a really interesting price.
My doubt is related with this field: RAM Size 64K x 8.
What exactly does it mean? I know what it means RAM but 8 blocks. How it works?
AI: It means that the RAM is ... |
H: how long will an 11w bulb last on 3 x 500mAh 3.7v cells
I have this question that I can't seem to figure out. I have an 11 Watt bulb and 3 500mAh 3.7V Lithium Polymer Cells. And the question is how long the bulb will last. Can anyone help me with the calculations?
AI: Looking at only power available and drain:
500m... |
H: Load sensing switch
I made the circuit here to automatically switch on my workshop dust extractor when I use a power tool. It works fine when used with a drill press or router. However with a Dremel 4000 it only switches on when the Dremel is at its highest speed. I imagine this is because the Dremel has an electro... |
H: ESP8266 "rom" boot code is overwritten when upgrade firmware?
You can flash the firmware using ESPTOOL with a command like
./esptool.py write_flash 0x00000 my_app.elf-0x00000.bin 0x40000 my_app.elf-0x40000.bin
this will overwrite the SPI FLASH chip with a new contents. But if you overwrite 0x0 region is the bootloa... |
H: How can I calculate time constant and charge time of RRC circuit?
This circuit is part of my time delay circuit. I want to calculate exact value of delay time. Please help me.
simulate this circuit – Schematic created using CircuitLab
AI: There are two time constants here. One is when the input is driven and the ... |
H: 4/5 band resistor - extra black band
I have two resistors which need to be replaced. I tried to determine the value, but it can't make sense of these black bands:
For reference the bands are:
brown - silver - green - brown - black
brown - silver - red - brown - black
Since a silver line can only be part of the m... |
H: Scoring a PCB across traces
I'm wondering if it's possible to score a PCB (such that I can easily break off the scored section) while still being able to have traces going across where the score would be. I have a rectangular board, and I'd like to have a little edge connector tab on the side of it for temporary us... |
H: Parallel networks and references
I have a very simple question regarding parallel RLC networks (or any similar circuit). When given a problem where the reference voltages and current directions are allocated 'strangely', is my intuition correct to make all voltage references positive on one side (top) and the curre... |
H: How do MCUs and RAM wire up for programmatic access?
I am new to electronics and microcontroller programming and need either confirmation that my understanding on a few items is correct, or I am in desperate need of correction on them!
I have a C-based server that requires about 2GB RAM to function properly. I am i... |
H: Superposition on a circuit with just one source
I'm trying to analyse this circuit (state variable filter):
All the places on the web I've found solve it first using superposition, creating an equation of the form \$ V_2 = kV_1 + kV_4 + kV_3 \$.
However, I can't understand how they use superposition in this circui... |
H: With regard to GPS signals, what is the significance of I-parts and Q-parts of Complex signal?
What is the significance of I-part & Q-part magnitudes and imbalances in the screenshot?
They are listed next to the red Complex signal diagram.
Imbalance of I-part: 4.7%
Imbalance of Q-part: 25.8%
Magnitude of I-part: 56... |
H: Very odd open-drain output design
I ran across a open-drain design and am baffled by the resistor between the nFET source and ground. There are only two purposes that I see it could serve.
1) It's series source termination, matching the impedance of a transmission line attached to the drain. However if this is the ... |
H: PICkit3 MCLR to Vdd Pull-Up Resistor
I'll preempt this by saying that I'm a software person whose education (unfortunately) didn't even touch on the most basics of hardware or circuits.
I'm attempting to program a PIC16f1709 microchip with a PICkit3 via MPLab X v2.3. The PIC is part of a larger board, but is curr... |
H: 555 as a Digital Coupler
I want to read MIDI data with an arduino (specifically an ATtiny85) for use in a synthesizer. The only method I'm aware of involves using an optocoupler such as the 6N138 found on this Instructable. It seems quite practical but unfortunately I don't have one on hand right now and shipping m... |
H: What knowledge and equipment do I need to build this device?
OK I am a Software Engineer dealing with both low level and C/C++/Java code with a Masters in Software Engineering but no knowledge of Electronic Engineering whatsoever.
I wish to build a device that operates transparently at the IP level and can be inser... |
H: Replacing a piezoelectric speaker with an electromagnetic one
I'm making this circuit:
(source: vk2zay.net)
where X1 is a piezoelectric speaker or ear piece.
However, the only kinds of speakers I can get in time to finish this project are electromagnetic ones (we found one in a Father's Day card, and another from ... |
H: Why does my AY-3-8910 sound so distorted?
I'm building a circuit driven by an Arduino UNO that controls a AY-3-8910 programmable sound generator.
The AY has three pins labeled Channel A, B and C. Each output is an independent sound channel.
I am piping the audio through an LM386 which then drives a small PC speake... |
H: Will an 0603 capacitor fit on an 0805 pad?
I am in a pinch and just submit my final board design to a pcb house. Unfortunately, I messed up the design and had an 0805 pad in a spot where a an 0603 should have been. I will be getting the boards in this Friday with a 2-day turn.
Can I get an 0603 to fit on the 0805 ... |
H: Will a diode conduct if one side is floating and one side has voltage applied to it?
I have a circuit that has a battery output voltage of about 7V and can also have a charger input that when plugged in will output around 9V. The battery/charger power a microcontroller (regulated down through an LDO) as well as a ... |
H: Obtain an accurate DC value in an AC+DC signal
Background:
My goal is to use an Arduino with two proximity probe sensors to achieve some output.
It is worth mentioning that the output of the proximity probe has two components:
DC output that determines the position or the GAP
AC component on the top of that DC vol... |
H: Opamp circuit has an unintended DC bias
I was fiddling around in LTSpice for a project I'm working on.
This circuit is a basic preamplifier and a low-pass filter. But this question refers solely to the amplifier stage. The opamp is the "universal opamp2" model.
However, the resulting waveform has a 4.5V DC bias. S... |
H: Inductance of a relay coil
I'm using a magnetic latching dpdt relay from Teledyne company. The value of inductance for the coil in the relay is needed and not given in the data sheet. The part number of relay is 422d from Teledyne.
How can I know it?
Is it possible to know the value without actually buying the prod... |
H: Vcc pin of TVS diode array
Bourns has various TVS diodes to protect Ethernet ports.
Most of them (for example CD143A-SR05) have GND, VCC and I/O pins.
I/O pins are for Ethernet signal line.
Why do these TVS diodes have VCC pin?
AI: Using a VCC rail in conjunction with unidirectional TVS diodes allows the device to ... |
H: Why does output impedance behaves this way
Why does the output impedance(Ro) of a common emitter amplifier is considered in parallel with the collector resistance(Rc)...as according to the KVL--->Vcc=IcRc+Vce+IeRe they seems to be in series....??
AI: If you have two resitors which have one common node, it is IMPOS... |
H: Removing spikes from multiple onboard power supplies
I have a board that is based around an STM32F303 and am using the onboard ADC/DAC, fed by a 3V power supply derived from a USB 5V input. The 5V also feeds a module, RD0515, which creates +/- 15V for opamps on the board. My problem is that the RD0515 also creates ... |
H: Purpose of input resistor in ADC circuit
What is the implication of the 1 Megaohm resistor in the schematics attached? Will I be able to detect the condition of the motor (running, not running, stalled)?
Part information:
MCU ADC (ADC type: SAR) leakage current is 1uA.
R3 (Load) is a H bridge (pair of PNPs (5CS) a... |
H: Calculation of a current in the Laplace domain
In the circuit below (working in the Laplace domain), I have to calculate \$I\$.
$$\begin{align}
&I=\frac{-V_L-V_C}{sL+\frac{1}{SC}}=\frac{-V_L - \frac{V_0}{s} - I \frac{1}{sC} }{sL+\frac{1}{SC}}\implies\\
&\implies\ I\Big(1+\frac{\frac{1}{sC}}{sL+\frac{1}{sC}}\Big)= \... |
H: PCB, Plated hole with annular ring on only one side
I need my pads for connectors to be plated so that the pins from the connectors can be soldered. But the bottom side cannot have copper pad/annular ring. I have made the pads as shown in the figure below. Bottom pad size is same as the hole size and the hole is Pl... |
H: How can I prevent reverse voltage in my stop/tail light design?
I'm looking to modify the rear lights on my 72 VW beetle to enhance ascetics and improve safety.
I intend to use LEDs to achieve this and feel that both the indicators and reverse lights should be pretty simple circuits. Once I've figured out how many ... |
H: Statistically, which embedded system is the most used in Cryptography/Security?
I am considering to buy an embedded system development platform (electronic board + software) for Cryptography and Computer Security.
Statistically, which embedded system is the most used in Cryptography/Security in Industry and persona... |
H: SPI communication with multiple slaves
I am working on a project that is using an ATtiny861A and this only has one SPI. If I want to hook up a radio and an external memory to the same SPI, will there be an issue sending data from the external memory to the radio? I know I can hook up the external memory and the rad... |
H: Altium: Surface Mount Test Pad Passing Through PCB
I'm working on a PCB in Altium that will sit inside an assembly above another board. The board on the bottom has a test pad, but once everything is assembled it will be inaccessible. Therefore, I am attempting to add two pads to the top PCB (one on the bottom layer... |
H: How to find voltage across X and Y?
This is the schematic diagram of the circuit
This is a homework question , which belongs to mcq type
It is about finding voltage across X and Y?
Is there voltage between x and y ? I wonder if there is a voltage across x and y, because they aren't connected , so how can a curre... |
H: Voltage transfomer without ground connection
today i bought a transformer 200v to 110v for my soldering station hakko fx-888D however it doesn't have a ground connection. Is there any problem if i connect the soldering station to it?
AI: Usually the ground connection on soldering irons are used for grounding the ti... |
H: Energy absorbed by the condenser
If the current \$i=0\$ the total energy absorbed is:
\$E_{tot}=E_C+E_L\$, where \$E_C\$ is the energy absorbed by the condenser and \$E_L\$ that absorbed by the inductor.
Now:
\$E_C=\frac{1}{2}C v^2_C(t)=\frac{1}{2} C \Big(\frac{1}{C} \int i\ dt\Big)^2=\frac{1}{2C}(\int i\ dt)^2\$... |
H: Serial Communication with rs232/485 and rj45
I am working a project where I want to connect and control, using Labview,
TDK-Lambda Power Supply
Process Vacuum Controller Ion Gauge (MODBUS interface)
They both have rs232/rs485 capabilities, just depends on a switch on the back of the terminal and both connection... |
H: why my LEDs burned with the right driver?
I am trying to connect, in parallel, 18 LEDs that have these specs:
LED
size: 10mm;
Voltage: 3.2V - 3.4V;
Current: 20mA.
Driver
Type/Model: MeanWell LPC-20-350 (datasheet: http://www.meanwell.com/search/lpc-20/LPC-20-spec.pdf)
From my calculation, by putting 18 LEDs i... |
H: Eagle PCB design issue
I have finished the schematic layout for my design which contains transformer. I also found the optimized design 100%, but the transformer background should be black while I'm having only portion of it black, any idea on how to do it?
AI: Your polygon pour is filling in (showing as blue). To ... |
H: Charging a 36V battery set with a 255W solar panel
I have directly connected a 255W solar panel (with Vmpp of 49.5V but can peak at 56V in full sun at mid-day) to the 36V battery set of my golf cart. This seems to have been working fine for months, as I am a light user of the golf cart (a few miles per day) in a s... |
H: How to generate a 1KHz singal on a PIC18F4450?
I'm looking for some tips and hints to move on. The 1KHz signal should exit the microcontroller at port RD0.
Thanks in advance.
AI: As requested, here are tips and hints:
Go to http://www.microchip.com and download the datasheet.
Read it.
No, really, actually read it... |
H: How to wire screw type banana jacks
I recently purchased some of these: Digi-Key Banana Jack. Unfortunately, I'm new and there isn't the supporting documentation I need to be able to determine how they're to be used.
Unlike other banana jacks, there is not a hole to feed the wire through and screw down on. I un... |
H: Voltage Drift on an Open Circuit (and how to get rid of it)
I'm trying to create a custom lick-port to detect mouse licking behavior. I am following a design published here that uses the junction potential between the mouse's tongue and the metal water spout to detect when a lick occurred, see image below:
To do t... |
H: DIY rubidium clock construction
I recently found my way onto a Datum x72 rubidium standard and had half a mind to turn it into a homebrew atomic clock, since I'm not exactly using it for a garage-based satellite business.
It seems there are plentiful examples of building atomic clocks using AVRs and PICs online, bu... |
H: PIC Microchip Keeps Resetting
I have a PIC16LF1709 20-pin 8-bit microchip MCU. I am programming it using a PICkit 3. I am able to successfully burn a program to the chip and run it, but it always seems to reset part-way through execution.
While programming the PIC, I'm letting the programmer supply the power, but I... |
H: How to make USB smartphone charger?
I want to make a USB cell phone charger. I know USB operates in 5 volts which means i need to drop down voltage if i have battery potential greater than 5 Volts. I have 12 volts sealed lead acid battery (SLA) of capacity 9AH. I need to drop down the voltage for which i am using L... |
H: Smoke detectors replacing - why? Lifetime of components?
I often see that smoke detectors "should be replaced" every 5, 10 or 20 years. Like on this website for example: http://modernsurvivalblog.com/health/did-you-know-smoke-detectors-expire/
The U.S. Fire Administration says most smoke detectors installed today ... |
H: Doubt about potential difference through a resistor?
First of all let me give you the schematic diagram of the circuit,
Here, how to find the current passing through 150 ohm resistor?
These are the things I have tried,
Since I want to find the current through 150 ohm resistor I need the potential drop across that... |
H: How electric devices can sustain at such a huge voltages?
This is a common experience.When we buy any electricity run device ,it is given with it's specifications like it's operating voltage,current ranges. Also,normally power supply is 240 V , 50 Hz.
But when we turn ON the switch, the electric devices have to fa... |
H: Considerations when repairing dimmer switch
I originally asked this question on DIY StackExchange. So far no answers and a suggestion to try on Electronnics, so here goes:
I have an IKEA lamp with dimmer switch which took a knock and immediately started outputting full brightness. I've read a little about how dimme... |
H: MOSFET driver IR2301S
I am trying to implement a brushless motor driver using an IR2301S driver. I started with testing the driver without MOSFETs. Here is schematic:
In the datasheet of the IR2301S is this picture:
If I understood correctly, I should see oscillating on LO if there is an oscillating signal on LIN... |
H: Making function using 2x4 decoder and one or gate
I frankly don't understand how to make it. I try to make but, I think it's wrong. How can I make it ?
Function is: $$f(a,b,c) = ∑(0,1,2,3,7)$$
My trying:
In addition using 3x8 I make:
AI: The problem stated in the question looks to be impossible to solve. I will tr... |
H: What proximity detection technologies can work through glass?
I'm looking for sensor options for proximity detection through a pane of glass. Something that will sit 6-24" on one side of a pane of glass, and be able to detect presence the same (roughly) distance on the other? I assume ultrasound won't work, but am ... |
H: CC2520/ATtiny861A pin configuration
I am looking to hook up a radio with an ATtiny861A microcontroller. The radio that I will be using is the CC2520 from Texas Instruments. The RESETn pin(on the CC2520) will allow me to put my circuit into a sleep mode and this requires me to have the reset pin attached to the MCU(... |
H: CS/SS pin configuration
I am using an ATtiny861a and I want to enable it to use SPI. In doing this I need to assign not one, but two CS/SS pins in order to communicate with a radio and an external memory. Does the CS/SS pin need to be connected to an ADC pin or could it be connected to a AREF, PCINT, or OC1A/OC1B p... |
H: I need help finding the equivalent resistance
Hello guys , i'm new in the amazing world of electronics , and im very confused with this circuit . Im supposed to find the Req (equivalent resistance , but dont know how in this specific circuit), plz help me out .
AI: The reason that this is difficult upon initial i... |
H: Current source with op amp and transistor
I'm building current source with OP AMP LM358 and MOSFET transistor IRF5305. Here's schematic diagram of the circuit:
I have two questions about it:
1) Maximal gate-source voltage of IRF5305 is +/-20V. Since V+ is 24Vdc, is it a good idea to add 10V zener diode between sou... |
H: How long can a brand new PCB last before additional protective coating is required if any?
I have just made several PCBs for a large project using the photoresist method. (I ran the boards through sodium silicate developer then through ferric choride) I then rinsed off all chemicals and dried the boards.
I believe ... |
H: LTC1775 Buck converter component question
I am trying to design a 12v,10A buck converter using a with LTC1775 and have gone through the calculations assuming a 40% inductor ripple current and a switching frequency of 150kHz. This gave an inductor value of 10uH and a mosfet with Rds(on) of 0.014ohm. So based on thes... |
H: Calculate battery duration
Maybe this is a trivial question, but I am struggling with it for a while.
I have an alkaline AA battery which is consuming 80mA for 8 seconds each 30 minutes. I need to calculate how many days it will last before reaching 1.1v. I know it depends a lot on the battery type, but let's say i... |
H: Mesh Current Polarity, Equation Setup
Practicing Mesh Analysis I came across this problem and te answer is really alluding me and I believe is just one polarity that I'm not understanding, the problem is the following...
Vs=10V, R1=100Ω, R2=50Ω, R3=25Ω, Is=2A.
Calculate the current I1 in amps that goes through ... |
H: Connector pins protection from overvoltage
I have a connector which has the following lines:
12V
3.3V
GND
SDA (I2C)
SCL (I2C)
The connector might get wet with water and I would like to protect the circuit from the resulting over-voltage in case the 12V line gets connected to the other lines.
Based on this schema... |
H: KiCAD 5 custom footprints
I want to use the TPA3251. Package is TSSOP 44 pins, 0.635mm pitch. KiCAD's built-in library does not have it. (as the subject indicates, I'm using KiCAD 5).
I created the library symbol without any trouble. Well, sort of no trouble — I had to change ownership of everything under /usr/sh... |
H: Trying to solve a RL circuit by hand but simulator calculates a value I do not understand
I have this circuit. V3 is just a trigger to close the switch, just ignore it.
The switch is open for a long time. So, the left part of the circuit is working for a long time and the inductor is fully energized. Current is ma... |
H: Laser pointer circuit
I've got a small red laser pointer from a chinese ultrasonic distance meter, which has a small regulator circuit (6mm x 7mm) with SMD components.
I guess that is a constant current to drive the laser, but I was unable to understand the circuit.
I've used a microscope and a continuity tester t... |
H: Power supplies with or without 'COM' and without ground port at all
This is probably something really simple, but I wasn't able to find the answer yet.
I've been using a power supply with both COM and earth ground, like the first image below.
To power an op-amp, I was using COM for grounding.
Then, I came across a ... |
H: Current source with unlimited cap drive op-amp oscillating
I've been trying to make a current source, and have finally gotten my hands on some LM8261's which should be an 'unlimited cap drive' op-amp.
The problem is, it is still oscillating.
This is the schematic and PCB layout:
I have tried to route the ground i... |
H: Is it possible to measure frequency upto 500Mhz with 50Mhz oscilloscope?
Is there a way to measure higher frequency measurements with a 50 MHz oscilloscope (eg rigol ds1054z)? Perhaps some post processing of captured waveforms? Or with the help of some adapters?
I have a Rigol DSO1504z digital oscilloscope.
Link. ... |
H: What is this connector called that looks like a small mono audio jack?
The thermocouple from my oven thermometer has a connector that looks somewhat like a mono audio jack, but smaller:
The connector is around 2.4 mm thick in the long, extended section and around 11.2 mm long.
Does someone know what this is called... |
H: What type of power connector is this?
I have one of those portable 16 Ah car jump starters that I want to use as a power pack for some 12v stepper motors. Rather than canabilize this plug, I am wondering if someone can tell me what it is called so I can see if I can find an unwired one on ebay or something to use. ... |
H: Mains earth and op amp ground
I was trying to power a transimpedance amplifier built with an op amp on a protoboard.
I only had a power supply that looked like the first image below (no COM, which I would have connected to GND of the op amp).
The answers I got for my initial question posted on this website were rea... |
H: wind turbine voltage multiplier
I am building a wind generator with a car alternator without a gearbox.
I know that the alternator is designed to spin at 5-10k RPM and the blades runs at 60-120 RPM so the alternator generates less than 1 volt.
My question is: Can I use a voltage multiplier such as a Cockcroft-Walto... |
H: What is a (side) current alarm?
On the technical sheet of a motor controller integrating two BTS7960B (picture below), the description of the 8 PINs on the board is as follows:
RPWM: Forward level or PWM signal input, active HIGH
LPWM: Reverse level or PWM signal input, active HIGH
R_EN: Forward drive enable input... |
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