# All Questions

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2 views

### Ni-Cd battery voltage indication of 100% charge

1.Hi,I have a Ni-Cd battery of 1.2 V and what is the voltage when it is 100% charged and for 0% ? Moreover what does that 1.2 V indicate.
7 views

### Using a DS3231 RTC alarm + MOSFETS to turn on a MCU

I'm using a DS3231 in conjunction with two IRLZ44N MOSFETs to switch power to a MCU when the alarm on the DS3231 triggers. The alarm on the DS3231 pulls the SQW/INT pin to ground and turns on the MCU ...
14 views

### How to choose Drain current for a JFET Differential Amp

I have to design a JFET differential amplifier with a current mirror. I am unsure where to start and what to set the biasing current to. Any help will be appreciated to point me in the right direction....
20 views

### Distortion in Transistor Amplifier

I want to design amplifier in 20kHz - 200 kHz range. I have designed following circuit using BC547 transistor. I have set VCE voltage to 6v and set Q point to the middle of the load line. But when ...
16 views

### Relationship between resistance, amperage, and propagation length of signal

n electrons sent into a wire of length L, and n/2 electrons sent into a wire of length L/2, diameter unchanged and wire material unchanged, does the "signal" of electron propagation reach twice as far ...
14 views

### Do PMOS Reverse Input protect on ORed power rail

As the title says, I have a power mux IC and two power inputs. I need them to be protected from reverse voltage input. The power mux i have already comes with a reverse voltage input protection but i ...
23 views

### Transfer function of a second order capacitive accelerometer

In order to find the transfer function of the accelerometer MMA7361L based on the information given in the data sheet 1 I first made a hypothesis that it a second order sensor since it has a ...
14 views

### Connecting a USB to UART converter to a computer's serial DB9 port

I have an APU2 that diverts any 'display' over a serial console (DB9F). For accessing the serial console, a null modem cable is recommended where the wires are crossed over. However, my computer does ...
25 views

### Looking for a consolidated datasheet for commonly used transitors

I found it challenging to look for individual transistor pdf datasheets with somehow different layout styles then extract common parameters. Is there any consolidated datasheet or table that lists the ...
12 views

### Selection of transistor

Suggest a transistor as common base mode and 220v input (emitter) 4v base To use it as a switch As it is used in water pump which is used directly by plugging in board that is at 220v alternating ...
8 views

### How do I calculate Vsig max here?

Is "limitation on the peak sinusoidal input" Vsig max? and if it is, what difference does it being "max" make and how do I get it?
6 views

### Build a T flip-flop with enable and reset using only a JK flip-flop (withous enable or reset) and some necessary logic gates!

So I was told to make such circuit asked above, I am thinking that if Enable is low then Q(t+1) will be just Q(t) (like 'keep') while if enable is high then check Reset, if reset is high then Q(t+1) ...
39 views

### Design a tuned BJT common emitter amplifier with some specifications

I've been 2 days trying to design such amplifier with the help of a book of Boylestad (Electronic Devices and Circuit Theory), but the best I came with was an amplifier that amplifies what it's ...
19 views

### Minimum Input Voltage of Buck Converter

How do I determine the minimum voltage for a buck converter to work? For example, in this Reference Design the minimum voltage is 166VAC. But what if I want to operate it at 100 VAC? What do I need to ...
10 views

### Floating Nodes Error in Simulation in ORCAD PSPICE

Does anyone have any insight as to what exactly is wrong with my f***ing circuit on Orcad/PSPICE my name is in the project name so I blurred it out for obvious reasons
33 views

### How do you call wire pins that can be used as jumpers with your breadboard?

I can't seem to find these things on electronics distributor websites. There is a bunch of various pins and connectors but I can't find these among them. What are they called? I tried "dupont 2.54mm ...
19 views

### Degradation in performance of pump

I recently purchased a Dc pump rated 3 to 6v~ On connectig it with a 9v battery(cheap one) it works well for 5~~minutes continuous after which its performance degrades to a level of it where it's ...
18 views

### Need to convert a 12V/300ma alarm output to a dry signal that will interface with my security DVR

Is there a relay that will work with 12V / 300ma input to close a Normally Open output? I've been trying to make it work with Ardouino board and a HiLetgo 12V 1 Channel Relay Module With Optocoupler ...
17 views

### Thevenin voltage (Voc) with a resistor in the way?

simulate this circuit – Schematic created using CircuitLab I'm still having trouble with how Thevenin voltages are obtained. Above is an example with designated terminals (red). What if there ...
20 views

### 555 timer as a voltage controlled oscillator, duty cycle query

I`m trying to create a square wave generator using a 555 timer but i noticed that due to the pulse width modulation as i vary the control voltage, the duty cycle changes so i was wondering if there is ...
17 views

### Advice for High Side Switch (High Current, Low Voltage)

I'm building a small LED driver microcontroller board and I'm looking for any advice y'all have on switching the power to it up to 9A (would take 3A, if necessary) at 3V - 5V, in a small package. I've ...
53 views

### Sensor data transmission without using a microcontroller?

What is the most traditional approach to getting sensor data onto a radio from an embedded device pcb that doesn’t utilize a microcontroller? Up until now, we’ve been utilizing a convenient firmware ...
55 views

### What causes my computer fan to stop briefly before resuming spinning?

I'm building a small fume extractor for soldering. I have a leftover desktop fan I'll use. I was unsure about the voltage needed, so I hooked it up to my power supply and stepped up the voltage until ...
49 views

### How to automatically reverse the direction of a motor without human intervention?

I am working on this project where I have an arm at rest want a brushless DC motor (BLDC) to automatically reverse: (I've added an image and text above for a visual reference) Given that I am taking ...
35 views

### I'm having issue getting thick tin-lead 63/37 solder on Alloy 42 lead frame

I'm using Kester 2235 flux and using robotic solder dip so heights are static. I'm measuring thicknesses using x-ray fluorescence, they keep coming up very low. Should I be using an initial scavenge ...
23 views

### High voltage Flyback transformer polarity

This circuit is a high voltage generator using flyback transformer. It works well, but i thought it shouldn't working by this polarity of the feedback winding ! I mean when the voltage on the ...
15 views

### Array factor of a 5-element array

How to find array factor(AF) of a 5-element linear array that is equally spaced,$$d = \frac{\lambda }{2}$$,having uniform phase$$\theta = 90$$ having triangular current amplitude distribution(1:2:3:2:...
59 views

### Checking if a device is safe to use

For someone with no knowledge in electrical engineering, is there a way to check if a device is "grounded" (?) and safe to use? It is not uncommon when shopping for appliances online (eg. lamps), ...
22 views

### Drive series of 1W led with mosfet

I've to switch on for a short time a series of 6 or 7 leds with a 24Vdc. Follow some details... power supply: 24VDC led: 1W CREE XRE Q5 link Power: 1W Voltage: 3-3.7V Current: 300-500mA this small ...
81 views

### Purpose of 1000uF capacitor in input

The board connected to power supply with 50-100m cable. There is C1, 1000uF 50V capacitor on input of board, next to power connector. Schematic of power circuit is below. I think it is for bypass or ...
53 views

### Voltage subtractor using op-amp

I'm trying to design a circuit that produces  V_{\mathrm{out}}=\begin{cases}V_{\mathrm{in}}-V_{\mathrm{cc}}/3 & V_{\mathrm{in}}>V_{\mathrm{cc}}/3\\0 & V_{\mathrm{in}}<V_{\mathrm{cc}}/3 ...
41 views

### Adding a callback for processing the UART data seems to cause issues with I2C interrupts

So I wrote peripheral drivers on STM32 and wrote a simple application to read the user input via terminal and respond accordingly. I am using interrupts for both UART and I2C but the way I previously ...
23 views

### Common Source Amplifier Pmos?

What is known as a common source amplifier is often built with an NMOS, where the bottom channel (source) is connected to ground. What if you switch out the NMOS with a PMOS, and the bottom channel is ...
38 views

### What does this chip do? And I want to get a datasheet - Top markings include: Analogix ANX6212

What does this chip do? Top markings include: Analogix ANX6212 And I would like to get a datasheet, if possible.
94 views

### How does this old fan regulator circuit work?

I was looking for an old fan regulator for a long timebecause a lot of people said that the power consumption of it was the same at high speed and low speed. This is a 50 year old fan regulator (...
58 views

### 10 Tb/s interconnect Question [closed]

i'm working on a design for a 10 Tb/s interconnect operating over a 2 km transmission distance. I'm planning to use TeraHertz modulators here with using OFDM. Is it possible?
36 views

### Why do x amp rated consumer electronics often come with >> x A rated BS1363 fused plugs?

I often find that consumer electronics from reputable brands come with fused plugs that are rated significantly higher than the actual product. I would have thought that the ideal fuse would be \\$x+\...
41 views

### Trying to control vintage amplifier (TEAC A-H500) with Raspberry Pi - what's the communication protocol? 8-bit bus?

I'm trying to control my vintage amplifier from Raspberry Pi - I want to create a nice little Spotify streamer that on playback start will automatically turn on the amplifier and set the input ...
31 views

### is there a small DC motor that could generate 50 watt and at same time located inside a tube full of water

Is a brush-less DC motor available somewhere that could generates around 50 W? Maximum OD of the motor to be 2.5 inches and to be able to be located in water medium we water flowing around it.
30 views

### DC Distribution System Numerical Problem

I have attempted to solve this problem but the answers don't match. Where am I making a mistake?
10 views

### AGC/3AG 1.0 Amp High Breaking Capacity with inline fuse holder (Automotive usage: 24 Volt battery)

I am looking for this specific type of fuse. First question is this a fact acting fuse or a slow acting fuse? Second question is there a specific item number / SKU / Part number for this fuse? Can it ...
25 views

### How to read such long range RFID tags?

I am impressed by the range of these these "long range RFID tags" or this item: Reading distance:3-15M How is this technically possible? it seems there are passive (no space to have a battery in ...
26 views

### Help identify gold plated SMD components,

photo shows NVIDIA Tesla A100 board. Please note the 4 SMD components on each side of the chip. Looks like gold plated ceramics. I have never seen components like this. Can someone identify this ...
16 views

### Circuit to detect AC vs DC PWM and only pass the DC power

If someone connects a 24V DC lightbulb to a 110VAC or 220VAC line, the result is catastrophic to the bulb. I'm seeking guidance to make a small protection circuit that can reside inside a 24VDC LED ...
170 views

### Obtaining 4-4.2V rail from 5V output of LM7805 voltage regulator

I'm creating a numitron clock with 4xIV-9 tubes (seven-segment filament displays) and have decided to illuminate them using shift registers controlled by an arduino. Each segment takes a voltage of 4-...
28 views

### How to determine regulator's components values?

The final goal is to have an output (u0) of 22 V. The only information given is the uBE value of 0.7 V and the maximum load current of 1 A. I'm having a hard time determining basically every value ...
26 views

### Can i use welding cable as primary coil for Tesla coil?

I am trying to make DRSSTC (see NOTE1) and struggle to find copper tube for my Tesla coil, so I'm looking for other stuff that I can use for the primary coil. Now I think, can I use welding cable like ...
20 views

### How do transformer winding strategies affect stray capacitance

I have a project that involves handwinding some rather compact transformers (toroidal cores about 0.5cm outer diameter; max number of turns on one coil of about 150), for which I am interested in ...