# All Questions

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16 views

### Trouble in understanding current flow in this three phase DC-AC inverter circuit

Shown in the figure is one of the six steps of a 3-phase voltage source inverter where switches 1,5,6 are closed. The tutorial that I learnt this concept from draws the following equivalent circuit of ...
29 views

### Is my STM32F103C8T6 bricked?

]2I recently started learning how to develop on the STM32F103C8T6. I got the Mastering STM book and followed it to run the first program, which was blinking the onboard LED. I ran the code and made ...
34 views

### Parallel Capacitors with different voltages

Let's consider a capacitor precharged to 5V. Now immagine to put it in parallel with a capacitor which has no charge. What does it happen? They reach a voltage in the middle? Does it depend on their ...
38 views

### Over-unity problem on Tesla coil

simulate this circuit – Schematic created using CircuitLab I have achieved overunity and have a problem how this could be measured so clearly but EE's say it can't be so as seen on this YouYube ...
20 views

### Different variations of SR latch

Wikipedia gives following circuits of flip flops: SR latch using NORs SR latch using NANDs Note that circuit 1 have R input at top and S below it. Also note that circuit 2 have active LOW inputs, ...
24 views

### Non-shortest path traces

Inside a Nintendo Switch I spotted some traces that take a meandering path to the RAM chips. What are the benefits of designing it this way, instead of taking the shortest path?
29 views

### How to calculate resistor values for a VGA DAC

I have an FPGA and want it to drive a VGA monitor. I want more than 3 bits of color so I need a DAC of some sort. So I want to make a resistor dac. My plan is to have 3 bits per subcolor. So total of ...
19 views

### CMOS inverter propagation delay

Let's consider a CMOS inverter. It is known that its propagation delay depends on supply voltage (VDD) and on output parasitic capacitance Cout (which is due both to its transistors' output intrinsic ...
17 views

### Identification of antenna parameters for calculation

Sorry if my question may seem simple, but I discover the plans of an antenna (RECTANGULAR COIL WITH MULTILAYER) and I can not identify b and h on this given schema, ...
50 views

### How to amplify voltage, i.e. turn 3v into 5v? [on hold]

simulate this circuit – Schematic created using CircuitLab If my circuit is supposed to run 5v, and an element outputs less than that (e.g. 2.5v in the sketch), how can I amplify it back to Vcc ...
33 views

### A multi rail dc to dc power supply circuit design; thoughts and recommendations

I am trying to design or put together a multi rail dc to dc power supply circuit using Texas Instrument webench power supply. My input for this power supply will be 12V and I will have 5 hot ...
29 views

### Control scanner without printer part [on hold]

My HP Photosmart B110a has a damaged printer part, but the scanner is still working fine. I disassembled the printer and connected all the electronics (except the motors) to the main circuit. The ...
25 views

### Forming synchronous SR flip flop from asynchronous SR flip flop

Wikipedia gives following circuits of flip flops: SR latch using NORs SR latch using NANDs Clocked SR latch using NORs: Clocked SR latch using NANDs: I understand how circuit 3 is obtained from ...
42 views

### Why SS and MISO of sensor is permanently high?

I have a brand new acceleration/giro sensor evaluation board which I want to interface with ESP32 via SPI bus. After spending few days trying to make it work, I have discovered that sensors SS and ...
17 views

### Why I got error: doAnalyses: iteration limit reached?

Trying to use dependent source B that its current depends on a voltage source, I get error ...
26 views

### Protection Devices in DC ciruits

I am putting together a design for a custom Electrical panel. The panel consists of mainly DC powered components (Sensors, Controllers). Components are to be mechanically positioned using a DIN rail. ...
59 views

### Where does the sum current of the three currents flow?

In the following star and delta connections, if each individual current enters via Phases R, Y and B, where does the sum of the three currents (that is Ia+Ib+Ic) flow after meeting at the common point ...
30 views

### Buck convertor calculation on Vout close to Vin

I'm currently stuck in calculating the right inductor for driving very bright LED's with The TPS92518 led driver. (http://www.ti.com/product/TPS92518-Q1) This is a 2 channel LED driver and on every ...
19 views

### Battery draining SLA 55ah [on hold]

Hi I use 2 x 55ah lead acid batteries on single ride on golf buggys. 1000w motor. Past 12 months having batreries failing in around 4 months. Tested by drop load and both are around 40 to 50%. What ...
25 views

### VDD on crystal oscillator to GND or +3.3V? (ESP8266EX)

Currently I'm trying to make a circuit for the ESP8266EX Chip and I've stumbled across the "Crystal Oscillator" - section. It's said that the ESP8266EX supports 40MHz, 26MHz and 24MHz crystal ...
6 views

### Wiring a ceiling pendant UK wiring [migrated]

I've done this before, but maybe because I'm replacing a ceiling fan with a pendant light the wiring is different. I have 3 brown wires one live 1 Earth (No neutral wire.) This is the end of the ...
35 views

### Energy-efficient method to fit a 7-segment display + computing, into a tight space?

Note: there's a 50/50 dis/agreement about this sort of thing on Meta (see here), so I'm hedging my bets that this will be allowed. I'm currently working on designing a device that has to be ...
33 views

### Is it ok if I use all pins on non AC connector for AC

I intend to use non AC connector Hirose DH40 and DH37 for single AC line (230VAC). Connector single pin is rated 30V 0.3A. They did also did a test for 100VAC for 1 min. Plan is to use two ...
53 views

### Advantages of Four pin mosfet

I was working with a three pin mosfet. However, a senior suggested me to go for a four pin MOSFET. Now, I wonder, if there is any difference between a three pin MOSFET and a four pin MOSFET. Is a four ...
42 views

### LEDs that can flicker at the frequency of 100 MHz (10ns) [on hold]

I want to purchase LEDs (white, blue, red and infrared) that can flicker at the frequency of 100 MHz (10ns.) Can anyone please suggest LEDs that will serve the purpose? And also if any circuits ...
17 views

### Starting and stopping of a Mod N Counter for a FSM in Logisim

I'm working on a circuit for control logic. I'm using a 3 bit down counter. There is a control signal that when it goes high starts the counter by presetting it with a value of 5. The counter is ...
38 views

### Lead Acid Battery [on hold]

I have lead Acid Battery which I found in my old stuff I took it out and check the readings with my multimeter the battery is completely dead so I opened the caps of the battery and put few drops of ...
24 views

### Rechargeable LiPo for Raspberry Pi without having to be unplugged to be charged

I tried researching this online but failed to find exactly what I'm looking for. I want to have a docking station for my Raspberry pi, where I just connect it to a micro-usb and it'll recharge the ...
33 views

### Looking for an AC socket that mounts to a PCB

I'm looking for an AC socket (U.S.) that mounts vertically (not right-angle) to a PCB for a smart power strip project. It should have through-hole or tabbed connections that I can solder into slots or ...
33 views

### How do motors without cooling fins cool down?

I understand that the fan on the motor shaft blows air through the motor fins thus cooling down the motor... However, motors without these cooling fins surely can't cool down the same way. I just don'...
37 views

### “Linear” Amplifier

For example, the "small-signal" gain we find for a Common Emitter amplifier is -gmRc, (assuming no emitter degeneration) Rc being the resistance attached between the collector node and supply. Now, if ...
26 views

### Solar Simulator White LEDs flickering

I'm making a solar simulator with 13 white LEDs in series, they operate in 20V/450mA in full brightness (YUJI VTC Series LEDs 135L). As a power supply I'm connecting 220V mains to a Variac ...
40 views

### Complex Amplitudes and Exp'l Increase/Decrease

The following are quotes from a textbook, If S(t) is represented as a rotating phasor, the angular frequency of the phasor can be thought of as velocity at the end of the phasor. In particular ...
50 views

### Understanding capacitive current

In the context of understanding neurons as parallel circuits (see for instance here page 12), the following formulas are used: C = $\frac{Q}{V} \iff$ C * V = Q $\iff$ C$\frac{dV}{dt}$ = \\$...
24 views

### RC differentiator negative voltage clamp for comparator protection

I am building an RC circuit with the capacitor on high side and resistor at ground, connected to a voltage comparator. simulate this circuit – Schematic created using CircuitLab I saw this ...
45 views

### 12v DC motor controller to 12v wiper motor

]3i have a pretty straight forward question, i think anyway. So im trying to power a 12dcv 20amp wiper motor with a 9-60v 20amp dc motor controller but the problem is its not changing speeds with the ...
27 views

### Current mode boost converter design

I was trying to design a current mode boost converter in CCM using a MCP1630 and the specifications of the design are as follow: ...
52 views

### Boost converter increase current

I have boost converter powered by 2 AA batteries (3v) which increases the voltage to around 40v. I have a 12v zener diode to cap the output to 12v. Regardless of the zener diode when I connect a strip ...
21 views

### How does Solar Cell efficiency relate to Band Gap/ Isc/ Voc?

I am trying to understand how does the band gap Eg relating to the solar cell efficiency. Efficiency is defined as VocIscFF/ Input power. if we have the same Voc * Isc product , that will translate to ...
71 views

### How to drive riding lawn mower ignition coil?

I have a ignition coil I scavenged from a dead lawn mower and would like to play around with it. The problem though is it is not like a standard car ignition coil and I have no idea how to drive it. ...
17 views

### ESP8266 ESP-01 internal pull-up at pin GPIO0? +GPIO2 doubt

I have a PCB prototype which uses an ESP8266 module, ESP-01, the first ESP model with a 4x2 male pin header, and I will interface the ESP with a microcontroller. My main doubt is about GPIO0 pin of ...
38 views

### STM32 - 2 MegaByte DMA Transfer ADC To SDRAM

I want to transfer 2 MB of converted ADC data into SDRAM. I'm using STM32F429 Discovery board which is shipped with a 4-bank SDRAM (1 Meg Bits x 16 Bits x 4 Banks (64-MBIT)). I've configured the ADC ...
15 views

### dc motor driver BTS7960

i have 24v 150w dc motor . and BTS7960 43A High Power model . arduino uno . the project is to control that dc motor by rotating it cw &ccw . i dont have any problem with coding ( i dont even ...
32 views

### Can I connect two MCUs directly to one micro SD card without additional components?

I am new to this community so I am sorry if I'm asking in a wrong place or something out of topic. I think I have considered everything. :) So, now the basic info: I am working on a project which ...
82 views

### How can I delay a digital signal

I am generating a video signal using an AD724 and a microcontroller, which is genlocked to another video signal from a camera, and am using an SN74lVC2G53 analog switch to switch between signals. I'm ...
31 views

### Ir high power remote

I want to take the output to the ir led of a remote control and output it to a much more powerful remote control powering a powerful led. A circuit would be appreciaed The scenario is side of a ...
23 views

### Li-ion custom protection circuit module (PCM) design and de-rating

I am designing a custom PCM (protection circuit module) for Li-ion cells provided by a supplier ( they offer PCMs but they do not meet our RF immunity spec ). The supplier-provided PCMs have a charge /...
31 views

### how to use a second power source to automatically switch on another

I'm working on a little car based project, where I have an inverter protected by a 40a internal fuse. I need this inverter to only recieve power when the ignition switch is on (i.e. when car is ...