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H: How many amperes to choose for a Schottky diode after a current limiting power supply?
I have a power supply (original Raspberry Pi power supply, datasheet) with 5.1 V which delivers up to 3 A. In case of a short-circuit or if more than ~ 3.4 A is drawn, the power supply will change to a short-circuit state.
This b... |
H: What material exactly is used in the shiny antistatic bags?
I have another question, and in discussing the root cause of the issue there with an experienced RF engineer, he suggested placing a piece of antistatic ziplock component bag between the two most important PCBs (the GPRS PCB and the main PCB with the affec... |
H: Ideal diode IC (TPS2419D) not working
I have recently integrated an ideal diode circuit based on the TPS2419D chip from TI.
The schematic is the following:
When I apply 48 V to the input of the DC/DC, I do get 12 V at the output of the DC/DC, but almost nothing at the output of the ideal diode.
I've probed the val... |
H: Is it right to route AC L/N on different layers on a PCB?
I'm working on a PCB for a trailing-edge dimmer. Is it OK to route the AC live and neutral in opposite layers?
In the image, you can't see the AC neutral (blue), behind the AC_L, but it is there.
This is for a 110 VAC, 1 A per channel. The AC bar in the bott... |
H: Thevenin Theorem Question
I am supposed to find the Thevenin equivalent of the above circuit. My method was to take the 33 ohm and 10 ohm resistors in series and turn that into a 43 ohm resistor. I then turned the 43 ohm resistor and the 15 ohm resistor into the parallel equivalent, which is exactly 645/58 ohms. I... |
H: H-Bridge blows the fuses in my house
Transistors: FDP18N50
Optocouplers: EL817B
I have been struggling with this for several days. I want to make a 230V AC/230V AC inverter that extends the wave to control the speed of a blower. When I have 12VDC from the power supply on the input and a 10W 12V light bulb on the o... |
H: How can I power a bulb filament with a mixture of series and parallel circuit?
I am trying to power a bulb filament that has a rating of 3.0 V and 2.5 A.
First I made sure the filament worked by powering it with a variable power supply and setting the voltage at 2.5 V:
This was successful in heating the filament a... |
H: Reverse current blocking for P-channel MOSFET
I'm using a P-channel MOSFET Q57 as a switch for current from VIN_ALW_GATED to +VIN_ALW when VIN_ALW_GATED > 17.259 V.
In case VIN_ALW_GATED was not connected to any reference voltage (floating), and we connect another voltage source to +VIN_ALW, how I can prevent back ... |
H: USB used for programming
I am working on a design for an STM32F103.
I use a Micro USB-B connector (as you can see in the following picture).
Can I use this USB to program my STM32 or does it only supply the microprocessor with power?
This would be the power supply with a regulator.
AI: The USB port of your STM32F... |
H: Input common-mode offset voltage ranges of op-amp
I'm using an MCP6V81 op-amp.
While trying to understand, I see that the output of the op-amp can't be greater than Vdd and less than Vss. If that's the case, could someone clarify how the common-mode input voltage ranges can be greater than Vdd by 0.3 V and lesser t... |
H: MPU6050 ESP32 No Acknowledge
I am struggling to get an acknowledge from the MPU6050 using ESP32 with Arduino framework. I am unable to derive if the problem is hardware or firmware.
I have copied Sparkfun's breakout board schematic, setting the FSYNC, CLKIN and AD0 pins to GND and SDA, SCL and INT to GPIOs 25, 26 a... |
H: What is the function of the Zener diode in this BMS schematic?
I am drawing the schematic of a battery management system (BMS) based on the BQ76920. The application circuit in the datasheet shows the MOSFETs for balancing the voltage of each cell:
I compared it with a github project with the same circuit. It uses ... |
H: Can I run a dedicated power source through along with Ethernet?
Instead of utilizing POE, what if I used a seperate power supply for power and Ethernet for data using 2-pair shielded Cat5. Has anybody ever tried this, or thought of it? Are there any theoretical problems?
AI: It have to be done in a way it is safe. ... |
H: USB 5V and 5V AC/DC Power Module protection needed?
Im designing a small board that with have an input 220VAC and with an AC/DC module will generate the 5V for my 5V components and then with a regulator I generate 3.3V for my 3V3 components.
There will be also and a usb to uart interface for development purposes.
T... |
H: Sensorless BLDC motor alignment methods
I have been trying to make a FOC for BLDC motor controlling, but I am stuck at the state that before open loop state which single alignment of the motor control. The question and the explanation is below :
I have applied 24V to the motor from a DC source and made motor's pha... |
H: 741 in non inverting - single +5V suppl;y?
I need to amplify a +1mV to +100mV input with a gain of 10.
I was thinking of using a 741 with this circuit
https://www.electronics-tutorials.ws/opamp/opamp_3.html
The specs say it's dual supply, however I don't ever remember using them with anything other than a single su... |
H: XL4016e1 maximum input current
I have an XL4016e1 dc-dc converter circuit,
the output of the circuit is 12V 6 A .
What should be the current value of the power supply to obtain this current?
thanks
AI: This is a step down converter. Refer to the 24 volt to 12 volt, 6A example in the datasheet.
The power efficiency ... |
H: Identify part and how/where to order it from
I'm trying to fix a board in my overhead fan unit above my oven (there was a power event at the house). I have located the chip that was burned, but couldn't identify the chip.
I was forced to purchase the replacement board and now have a good ID on the part needed. I w... |
H: Why are the voltage ratings of switch contacts so much lower than breakdown voltage?
I need a switch for a high voltage application, say 5 kV, and I'm looking at relays. From a breakdown voltage standpoint, a contact with a 5 mm gap should be able to withstand 15 kV, which is 3x what I need, so I figure it should b... |
H: Is it possible to use two N-channel MOSFETs as motor driver with one driving and the other being used as a brake?
I have two PSMN7R5-60YLX and also using a IR2101S. I can use the 2101 and the MOSFET to drive the motor just using one of the drivers on the chip. Is the circuit below correct to use one as a brake (t... |
H: How does one choose the overdrive voltages of the transistors in a differential amplifier?
Question
Hi there,
So in the following image taken from Razavi, the part highlighted confuses me. He states the sum of all the overdrive voltages in each cascode branch is equal to 1.5V. Now, is this 1.5V because that's Vdd/2... |
H: Value of resistor clarification
I'm using this device - USB2514B
Table 3-3 says that the required resistor value is: "47 - 100 kohm". I assumed that the 47 was 47 ohms and not 47 kohms. I used 10 kohm resistors in my designs. Everything seemed to work OK. Now I have some boards that do not work consistently. I repl... |
H: Measure a PWM signal with an oscilloscope
I am new to electronics and now I wanted to try to use an oscilloscope to measure a PWM output signal.
I made a simple circuit with a Raspberry Pi Pico microcontroller and connected an LED on a breadboard with a resistor to a GPIO. I wrote some code to use PWM on this GPIO ... |
H: How to choose an appropriate N-FET for a BMS?
I am drawing an schematic for a battery management system (BMS) based on the BQ76920 and I have trouble with the N-channel FETs. How could I know an appropriate part?
This is the schematic:
I am following the datasheet design guide and it says something about voltage a... |
H: Effective Mass of Electrons
In electronics, the fact that mobility of electrons is higher than the mobility of holes is frequently used. How can we explain this using effective mass of electrons and holes ?
AI: Effective mass is not a good way of thinking about this.
Conduction in both N and P type semiconductors o... |
H: Voltage loss on drain to source using PSMN7R5-60YLX
I am using a IR2101S to drive a PSMN7R5-60YLX logic level N-channel MOSFET. My battery is 12.59V but the motor is only receiving 7.62 volts. The signal coming out of the IR2101 is exactly 5V to the gate of PSMN7R5-60YLX. Can someone teach me how to read this da... |
H: Control 12V 90mA alarm from 2N2222
I have an alarm rated for 12V 90mA. I want to turn the alarm on/off with a 2N2222. The base of the 2N2222 is connected to an ESP32. Circuit diagram is attached. Will it work?
AI: Placing a resistor (10k to 47k) across the base-emitter of Q1 prevents false turn-on in case of a phys... |
H: When the transistor is working as a closed switch, is the collector current equal to the emitter current?
When the transistor is working as a closed switch like the one to the right in the attached figure, is \$I_{C}=I_{E}\$?
In other words, is \$I_{C}\$ gonna make it down to the ground?
AI: The collector current ... |
H: Need help driving the enable pin on a TPS2595 with a voltage divider; not exactly sure which method is better to use
I'm a hobbyist at best, and am trying to overcome the learning curve as far as pull-up and pull-down resistors, N channel transistors and P channel transistors, etc, etc.
I've got a USB Type-C charge... |
H: How to find datasheet or pinout for this DC-DC IC? OB2560NAP
I have this power board on a WiFi extender and I'm trying to find the datasheet for this IC.
I believe this is the switching IC that generates the low 3.3V voltage from the high ~220V input voltage after passing through a coil and a capacitor
I cannot fin... |
H: Open-loop BLDC motor control using SPWM
I am a student who is still very new to developing sensorless FOC software. What I'm trying to do now is to open-loop control a BLDC motor using SPWM (to get theBEMF values required for the close loop.)
I installed the necessary hardware for this and wrote the software for ... |
H: Keysight bandwidth and rise time
According to the following application note from Keysight, one way to know what device to take for measuring a signal is to measure the rise time. Then according to the rise time of the system under studies, the bandwidth of the measurement device can be known. The formula is the fo... |
H: Capacitor for quartz crystal in harmonics
I saw a FM transmitter radio circuit, which was an easy one and had a 20 MHz quartz crystal, on internet. It promised to fix the frequency at 100 MHz. I soldered the components together and tried at home. It worked as expected. As the transmission was online, there was sile... |
H: 9 pin npn transmission relay issue
I've visited this site before never posted until now.
I just recently graduated with a bachelors in electrical engineering, and I'm trying to teach myself car electronics. I ran into this 9 pin relay that is supposed to be for a transmission. however I'm running into an issue when... |
H: PNP: What happens if the base voltage is higher than the emitter voltage?
Can a PNP transistor switch a 5 volt load such that in the off state the base is supplied with 12 volts and the on state is pulled to ground (Vb > Ve)?
I remember hearing that the base voltage needs to be lower than the emitter voltage, but I... |
H: Why P-Ch FETs values are in negative?
I have a doubt about why the P-Channel FET values in the datasheet are negative:
The reason why I am asking about this FETs is that I am drawing the schematic for a Battery Management System based on BQ76920 and the P-Channel FET Q3 is used to keep CHG terminal away from any v... |
H: How to design a schematic and PCB for an ADC using separated grounds
I want to measure a DC voltage with very high resolution (uV) and send the value to a PLC (based on an Arduino Mega.)
Initially I selected an ADS1115, but I got some power noise due to loop currents (discussion in this question). I decided to repl... |
H: Safe Operating Area
This is my LDO. 3A part.
Input is 12V
Output is 5V.
Load current is 2A.
As per Figure 2-41 on page 15, at 85degC, I am limited to 0.2A of max load current.
How can I get the 2A load current with the Vin-Vout of 7V?
If I calculate the Tj of device at this condition, it is = (14*56)+85 = 869degC... |
H: Can unused USB Type C pins be shorted together?
Can the unused USB Type C connector pins be shorted together?
Can someone please verify if my terminations for the connector pins are correct or do they require modifications?
AI: No. It's not advisable to short them together.
Leave them unconnected. |
H: Origin of the signal in an oscillator composed of a Schmitt trigger and an integrator
Following instructions, we built this oscillator as part of our electronics course:
I was surprised at first that we could get those signals without any initial signal connected to the op-amps input. Is it correct that the op-amp... |
H: Increase the bandwidth of an RF transformer
I'm building an RF transformer for a custom application (~500KHz to ~5MHz) and my band edges are bumping into the roll off region on the transformer. It's not the end of the world, but it would be nice to increase the bandwidth to avoid this. Is there any practical way ... |
H: How do I convert a battery's 3.7 V, 2.7 A input to 24 V, 400 mA output? 12 V, 800 mA would also work
I want to use a single Li-ion cell to drive a 24 V, 10 W PTC heater cartridge in a cost-effective manner with closed loop control from a MCU (RPico + 10 kΩ NTC thermistor).
Is boost or boost-buck suitable here? Are ... |
H: NAND gate with two vs. one BJT transistor(s)
Why is everybody discourage from this paired NAND BJT Transistor "design"? I already saw a few posts where somebody asked something about the paired BJT NAND "design" and the answers only say: don't do it like this, use only one transistor and as many resistors as you wa... |
H: Fast unidirectional level switch from 5 V to 3.3 V
I came up with this circuit. Is it good or bad to use diodes? In my opinion, this is better than a divider or a FET, at least faster, as you can see from the waveforms. Will such a circuit create bounce and noise? My oscilloscope has a bandwidth of 50 MHz and does... |
H: Inverting buffer
I want to buffer a signal with a 7404 IC, but this is an inverting IC. With feedback from the input to the output the signal becomes non-inverting again. Is this method correct and can it be used in circuits?
AI: All you're doing there is shorting the input to the output which at best just passes t... |
H: How to automatically change the project name and rev in the output file name in Altium 22
How could I make the project name and rev name change (possibly from the parameters) in the output generation file names in Altium 22?
Right now I rename them individually but that's not very fun.
AI: This can be done in outjo... |
H: ESD safe soldering without PE
I live in a very old house that has no PE in it, so I can't ground the tip of the iron and myself as I should to solder in a ESD safe way. Is there any method to improve ESD safety of soldering, when I work with static sensitive components? I have the following idea, and I would like t... |
H: What's the best solution for creating a magnetic field around a small cylinder?
I'm a beginning electronics hobbyist so forgive the naive question.
I'd like to have a small cylinder (1cm radius, 3-4cm length) where I could control a magnetic field around the cylinder with voltage.
Basically, if you were looking dow... |
H: CAN bus transceiver as I2C differential driver is not working
I am trying to make a differential I2C bus signal that is compatible with SparkFun's QWIIC.
OK: convert the standard I2C's SDA and SCL to TX/RX lines using P82B96D
NOT WORKING: convert TX/RX to differential signals using PCA82C251
Below is the schemati... |
H: What does a 9 A battery do to a 3 A motor when using the battery for movement?
I am trying to figure out why my battery keeps discharging so quickly. I have a 12 V, 9 Ah (valve regulated) SLA battery that I use on the bench to test motors. I write a small program, test the source, and then attach the hardware while... |
H: Recommeneded method to monitor rotary position and speed of machinery shaft
I am building a piece of industrial machinery that will operate between 10-200 RPM. I would like to know the rotational position and speed of the shaft (2in diameter steel crankshaft). I am currently considering building a small attachment ... |
H: Analysing the behaviour of inductor in the circuit
Suppose we have an L circuit with DC power supply of emf \$\mathscr{E}\$
simulate this circuit – Schematic created using CircuitLab
By KVL,
\$\mathscr{E}=L\frac{dI}{dt}\$.
This suggests that \$\frac{dI}{dt}=\frac{\mathscr{E}}{L}\$
As at \$t=0\$, \$I=0\$
So, curren... |
H: Is reading multiple buttons presses with ATtiny analog input a reliable method?
I need to read the input from 8 different push buttons on an ATtiny microcontroller.
After researching how to do this with the least number of pins, I found out about using a voltage divider with resistors and reading the input voltage ... |
H: How can I estimate the inductance of an inductor operating at different frequencies than the test frequency?
I am looking for a 10uH inductor to operate under 200kHz. I found this inductor, but its test frequency is 100kHz instead.
How can I determine if it's ok to use this inductor? Is there a way to estimate the ... |
H: Understanding PID controller output value
Consider a PID controller that needs to regulate the temperature of a small object. This will be implemented in software in a microcontroller.
A thermistor is closely bonded to a heater (a small 3 watt power resistor driven by an 8-bit PWM through a suitable MOSFET.) The ... |
H: How often can an ATtiny85 be flashed?
I wonder how often I can flash an ATtiny85 before the EEPROM will give up.
Solved
Sometimes it is just on the first page of the datasheet:
AI: It reads on the first page of the data sheet.
EEPROM is specified for 100000 write/erase cycles.
It does not depend on how often you do... |
H: 74HC221 negative edge trigging
How to use 74HC221 for output variable pulse width on negative edge.
I tried connect B and MR pins to HIGH and A pin to input as tells in datasheet. But it give huge pulse like 1 second.
Probably I must use RX and CX pins but don't know how to use and datasheet doesn't tell.
The pul... |
H: Is this way of maximum current calculation correct for this voltage regulator?
Regarding using the LD39050PU33R voltage regulator which is 5V to 3.3V fixed voltage regulator without any heatsink, its maximum current is given as 500mA. I was trying to figure out how they calculated this 500mA. So I tried to calculat... |
H: Understanding the flux linkage in transformers
I am having difficulty understanding the concept of flux linkage in transformers, particularly how the secondary winding receives its flux when all the flux is said to be confined to the iron core. I understand that the primary winding produces an alternating flux when... |
H: Can I charge 604050 LiPo battery using USB charger and single resistor?
The battery I got off Aliexpress has a protection chip:
I'm wondering - Will the chip protect the battery against overcharging if I use a standard 5V USB charger and a single resistor in series?
EDIT: I'm fixing a toy worth fiver. There is no... |
H: How does a bootstrap circuit work and how can I calculate the resistor and capacitor values?
I am designing an H-bridge with an N-channel MOSFET to control a 12V - 1.35A DC motor. The H-bridge will be controlled with the digital outputs of an Arduino. I did some research and found that I need to use a bootstrap cir... |
H: How to sense if a heater is plugged and on
I want to remotely check if one of my home sockets (which happens to power a heater) is transmitting current or not. I do this as a hobby project, so my main priority is to learn through the process of building it, therefore I don't want to buy 'ready-to-use' devices. Also... |
H: Basic capacitor in circuit
I’m new with electronics. I really don’t know how to search up this circuit. This circuit will make the LED turn on when it has microphone input. Could someone explain or suggest what should I search to know how this works?
AI: I have no idea why someone added C2 there. It will probably ... |
H: How to limit current going into DC/DC
In my project, I am using 12 solar cells in series as a power source. This is the link to the cell. Doing that will give me a power source of (3.6W * 12 = 43.2W) maximum and output voltage is (0.6 * 12 = 7.2V).
I want to use this source to power some sensors, such as this curre... |
H: How to determine power needed for an IC
I want to use solar cells as power source. Let's say I am using 12 cells, and that gives me 43W of power. I will use this power source to power multiple ICs, such as this current sensor. How can I determine how much power the sensor consumes? I want to know this because if I ... |
H: Equivalent impedance of a circuit
I'm trying to figure out the equivalent impedance of the right side of this circuit (so the capacity, inductance and right resistance) :
I see this result in the solution of my exercice:
But I don't see how L et R are in parallel, are they not in series?
AI: The point of view for... |
H: How can I connect multiple potentiometers (~20) to my Arduino without having to have 20 analogue pins?
I'm trying to build a MIDI controller and I'm looking for a clever way of using 20 potentiometers without having to have 20 analogue ports on the Arduino. So far all the functionality I need is for every potentiom... |
H: What is a chip generator?
I've been trying to learn more about the RISC-V environment. I've encountered a chip generator called Rocket Chip.
What is a chip generator, and how does it differ from a core? I'm trying to understand how and why it is used.
AI: A chip generator is a tool that automates the process of des... |
H: Finding equivalent resistance if each resistance is 100 ohms
The method to follow here is wye delta transformation, the resistors across red and purple nodes are in series so 2R and using delta to wye in green-pink-blue, and pink-black-blue
after that there are many options to convert delta to Y or Y to delta like... |
H: Logic signals have too high a voltage - Solved
I am trying to control a 5 inch display from a Raspberry Pi Pico controller. I am using a display from BuyDisplay.com which uses the RA8875 driver chip and has an 8080 parallel interface (Note: BuyDisplay have changed their product line since I brought the display so o... |
H: Where and how are the carrier and message signal multiplied in this circuit?
I have this circuit diagram of an AM modulator and I am trying to understand what is going on.
I know that the c(t) is taken from the collector of transistor Q1 and the multiplication of signals : m(t)c(t) is taken from the collector of tr... |
H: What happens when a CC/CV charger fails to give the required output voltage during CV charging and instead provides a lower constant voltage?
Lets say that I have a CC/CV charger based on buck topology and it is charging a 12V lead-acid battery through a solar panel. The lead acid-battery is being charged in CV (C... |
H: Which model of MBT desoldering station is this?
From Commodore 128 Complete Restoration and Board Repair @ 11:55, Raymond, the chap doing the desoldering, appears to be using one of these:
There is, however, no model number on the front.
From an ancient eBay item description, I found one (and the image above) desc... |
H: What value will be assigned to x, is it a or ~x?
I have some Verilog code for which I am unsure of the outcome of the non-blocking assignment of x as shown below :
always @(posedge clk, negedge rst)
if (~rst)
x <= 1'b0;
else
begin
x <= a; // Some value by default.
if... |
H: Power Regulation
I have a Li-Ion 3S1P Battery Pack with built in BMS rated:
Typ. Capacity: 5000 mAh
Nominal Voltage: 10.8V – 11.1V
Charging Voltage: 12.6V
Discharging Voltage: 9V
I need to power an STA540 in stereo plus bridge drive configuration (page 11/25) and I would like to regulate the power supply. If I use ... |
H: Jack audio 3.5mm PJ 215 (PJ 325) pins
I'm doing a simply audio frequency power amplifier circuit on breadboard. The input is the audio output of laptop or smartphone. I need to bring the input into the circuit:
I have this thing, it has 5 pins:
I'm going to use it to connect the audio to the breadboard. However, ... |
H: E-Ink with Atmega and avr-libc
I am trying to understand how to drive an E-Ink display like the Adafruit 4196 with i.e. an Atmega328 with avr-libc.
From what I could learn so far, I would write the image/text to a frame buffer and push it to the display when done. Because the 8k frame buffer needed for the 200x200 ... |
H: Applications for Comparators Stable in Linear Region
These two comparators here MAX913 and MAX9013 are comparators that do not contain hysteresis. They are advertised to remain stable in the linear region and not exhibit instability for slow moving signals at the threshold.
I have two questions:
Wouldn't other com... |
H: Why can't I get rid of shoot-through in my half-bridge circuit?
I am building a class D amplifer and I have getting shoot-through despite my best efforts to mitigate them using dead-time, miller clamping, and using high V_GS_threshold MOSFETs.
Here is the circuit on LTspice:
The problem occurs when the high side s... |
H: How do D flip flops know the correct count sequence?
Let's say we want to show the count sequence 001->010->100->111 using D flip flops. Next step would be making a state table.
After simplifying using K-map, we get D^A=C', D^B=B', D^C=A. Then I built the circuit with two 7474 ICs and it works. If the counter star... |
H: How can I avoid twisting wires in a circuit that rotates?
I am working on a project where I used a hollow pipe whose one end has a circuit board so that the wires will go through the pipe to the other end completing the connections. That pipe has to be rotatable, too. Rotation speed will not be too high, it will b... |
H: Help with MOSFETs to switch sensor on and off
I have a question, I have noticed similar solution for voltage divider to measure voltage on battery with ESP32 using one pin to enable the divider and have it otherwise off the voltage to save power. My question is if the same principle can be used for sensors, let's s... |
H: TP4056 / thermal pad
I am preparing a circuit using a TP4056. This circuit has a thermal pad. The datasheet says that this pad must be connected to ground or nothing.
However, some forum discussions talk about connecting it to GND or even VIN. Curious, I took apart a commercial module implementing a TP4056 and inde... |
H: Why does this circuit stop breaking down with a stronger flyback diode?
On a PCBA, I am using a LED driver to drive a high-power LED. Here is the schematics:
V_IN = 16 V
R_OSC is set so that the gate of the MOSFET is controlled at 150 kHz
R_CS is set so that the current in the LED is 1.5 A
Q1 = STT6N3LLH6 (V_DS =... |
H: Identify PCB component
Last week my living room thermostat "exploded" when adjusting the room temperature. Well, something inside sounded like exploding and since then it behaves erratically: the measured temperature shows 40 degrees C and the temperature-setting goes up and down automatically.
I'm trying to fix it... |
H: DI2C differential pair with controlled impedance?
on my project I'm using two PCA9615DPZ chips to extend an i2c bus between two boards.
The situation is:
PCA9615DPZ -> 15cm track -> connector -> 1m cable (CAT5) -> connector -> 15cm track -> PCA9615DPZ
But I have a couple of doubts:
1 - Do I have to use differential... |
H: RC circuit oscillator
I want to make a simple RC oscillator circuit that produces waveforms of
How can I do so?
AI: Two options:
Use 555 to generate very low on-time. I'm not sure whether it'll be practical as you may end up with ridiculously low component values.
Generate a clock with 555 or relaxation oscillat... |
H: Thermally insulating peltier cell
I'm trying to build a small cloud chamber using peltier cells. I've been using a TEC2 25408 and a cooler master 412S. So far I've tried to measure the lowest temperature the peltier can reach by placing it on the top of the fan cooler using thermal paste. With this setup I was able... |
H: Why is my oscilloscope’s output stuck at 0?
I am new to using oscilloscopes. When I was consistently getting zero voltage in an experiment I was doing, I decided to test whether my oscilloscope was working properly.
I set up a very simple circuit consisting of only a power supply at 3 volts and a resistor. However,... |
H: Electrical fast transient waveform (switching circuit) load
I am simulating a circuit to model the EN 61000-4-4 waveform for electrical fast transients using LTspice. The idea is to have the generator for some in house testing.
Here is an old question I have that shows some of the progress done so far.
The wavefor... |
H: Why do some DC to DC converters use high inductor values (ie: 220uH or more), while some of them use much lower value inductors (ie: 3.3uH or less)
I've noticed that many DC to DC converters that have have almost the same current output will have inductors that vary vastly in their rating.
For instance, I've got tw... |
H: Controlled impedance stackup questions
In this stackup (I know that it is not the best stackup but it is a general question,) if I choose to use controlled impedance on L4 (let's say 50 ohm), what is the reference that needs to L4 signals?
It's a stripline so it should be two layers (3 and 5.)
Is it possible to rou... |
H: Complex number or absolute number for impedance
I am reading about high speed PCB layout design from TI (Texas pdf)
This document mentioned the software AppCAD from Agilent to calculate impedance. Here is the snapshot.
My question here is whether this Z0 a complex number or not.
If it omits imaginary part, why wil... |
H: Can a small signal BJT handle small currents of reverse voltage (Vce) for a short time?
I have this piece of circuit with a 12V supply. I think it will work better in my application without the reverse diode. Do you think it can handle the reverse voltage of C8 that remains charged for a minute or so until it is d... |
H: Transmission Line Powering Load
Consider a long transmission line (4 km). Its a single conductor line with the inner conductor insulated. The outer shell is steel ground.
Consider two scenarios.
Scenario A: 120 V DC power supply, positive is hooked up to long transmission line, which is connected to 30 Ω load. Nega... |
H: Input resistance of an op-amp circuit
I need to find the input resistance of this circuit. There are two parts of this exercise:
The first one is to find the input resistance of the circuit without the capacitor.
The second is to the find the input resistance of the circuit with the capacitor ( C = 1nF.)
It is no... |
H: Find the equivalent resistance
I have to simplify the following circuit by using equivalent resistance. I know it probably should be very simple to do it, but for some reason, I can’t tell if the two resistors in the “internal” mesh are in series or in parallel with the other resistor R, in the external mesh.
MY G... |
H: Input resistance of an inverter op-amp circuit
I need to find the input resistance of this circuit. There are two parts of this exercise:
The first one is to find the input resistance of the circuit without the capacitor.
The second is to the find the input resistance of the circuit with the capacitor ( C = 10 nF.... |
H: Connecting FETs to make a push pull GPIO
We have a circuit that generates pulses via GPIO. We use FETs for the push-pull mechanism.
Our schematic:
Description of the push-pull mechanism.
According to this source, connecting two FETS like that is a bad practice which can cause short-circuit.
Should we change our ... |
H: What is the purpose of this diode in the battery management system schematic?
I have a doubt about the function of the diode D6 shown in this schematic
The schematic is for a battery management system and the diode is between the +,- terminals of the total voltage:
I do not know about that diode since I could not... |
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