# Tagged Questions

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21 views

### What is the function of 'Serial time code message (ToD) (RS-232 serial line)' as provided in a specification of distribution amplifer? [migrated]

What is the function of 'Serial time code message (ToD) (RS-232 serial line)' as provided in a specification of distribution amplifer? http://spectracom.com/products-services/precision-timing/epsilon-...
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### Altium simulation time

I am currently working on a quite big project and I use Altium to simulate my overall circuit to make everything works as I expect it to. I have something like 10 sheets linked to each other with ...
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### MATLAB using rand to test for time invariance

So I am given a certain system: y(n) = 10x(n)cos(0.25pi*n + 0.1pi) And I am to test if the system is time invariant by plotting two input signals x(n) and x(n-2), and their corresponding output ...
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### Looking for time delay relay or relay circuit that can be reset

Need relay control that results in a closed contact (dry) that is held for 1 minute If during that one minute another signal is received (dry or not) the 1 minute countdown resets. The actual ...
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### How to make a circuit that generates 50mA current at +1.8v within 10ns rise time?

I am using Atmega328 MCU to control a SRAM IC and it is required to power up the IC using a source that can deliver 50mA current at +1.8v within 10ns rise time without any voltage drop. unfortunately ...
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### Getting Clock/Time information from PC to an STM32F4

Assume I connect a microcontroller board (like an STM32F4) to a PC via USB. Is there anything in the USB communication protocol that contains host clock data? In other words, can I sync the ...
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### Capacitor rise/fall time varying with supply voltage

While testing the capacitor voltage fall times for my board at 3 different voltage levels I see that for 6V the fall time is higher than for 18V. I checked the same on a breadboard with a capacitor ...
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### Switch in Circuits

I am really confused about what happens to the circuit when the switch is open or closed. What does t=0 , t=0+ , t=0- , t<0 and t >0+ mean ? what does it mean if the switch has been in ...
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### Need help understanding the concept of “Circuit model of a discharging RL circuit”

I don't understand the statements for t<0 and t>0. Why does this happen?
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### time it takes for the voltage to achieve 7 V

C1 = 56uF C2 = 12uF R = 12kohm E = 13 V I have this circuit and I want help to find out how long in takes for the voltage Uc2 to achieve the value 7 V? I have calculated the time constant to 117 ms, ...
508 views

### Why are my reed relays releasing 10x faster than spec?

I have Magnecraft W171DIP-25 reed relays (datasheet). They are DPST relays with a built-in coil suppressor (according to datasheet). Their listed response time is 1 ms, and, following the logic of ...
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### I have this timer circuit. Push and release vs push and hold give me different times

I have a timer circuit which I slightly modified from the one in this link I have an image below of what my circuit looks like. My problem is this: When I push my start button and immediately let go,...
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### Relay turn off delay

I need help with my project. I want to design a circuit for my car. It goes like this: Blinker on car is made with 1-filament bulb. I want to use this bulb as indicator and as DRL (made by PWM - ...
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I want to make an extremely power efficient node that can receive a signal and determine what to do with the information it received. Since receiving requires a lot of power, I want to occassionally ...
157 views

### Could a computer technically run without time measurement?

I just asked myself if a computer could technically run without time measurement? With time measurement I mean the human-invented method to measure season and day/night cycles: a year has 365 days,...
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### VHDL: How to change the resolution of time printed using “now” in VHDL to file or terminal

The "now" is usually used if one wants to print simulation time to screen or into a file. I need to print simulation time in ms into a file. However, using now with writeline into a file is giving me ...
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### DS1307 timekeeping date significance (leap seconds?)

As part as a hobby project I built a relatively simple BCD binary LED clock using a PIC micro controller and a DS1307 RTC. Upon battery power loss the DS1307 resets back to 01/01/00 00:00:00 which ...
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I need to take one sample of a fast changing signal at exact time with high precision. Slow sample rate ADC's have better accuracy, but I wonder about actual aquisition time - the time at which ADC is ...
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### When does an RC Transient period end?

I have struggled with this question and read many articles and watched youtube videos but to no avail. For this circuit the time constant or "Tau" is 80 micro Farads (or$$80*10^-6$$) My issue lies ...
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### propagation delay (low -> high / high-> low)

i build a 2x2 bit multiplier circuit where i take a number (a1a0) and multiply it by (b1b0) . and im asked to calculate the time propagation from high to low , and from low to high for every input to ...
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### Fall time for integrator with a large resistor

I know how to find the Outputvoltage when the circuit is "turned on" (Input x DCgain x (1-exp(-t/a)) , a=time constant , t=time )..but.. How to calculate how fast the output voltage will go to zero ...
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### Detecting fast laser pulses

I'm building a laser target with photoresistors and a 90FPS camera (which will probably become CPU bottle-necked) and when yesterday I went to shopping I just saw a barcode scanner and begun thinking: ...
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### Find settling time of ADC

In an assignment, I need to find the settling Time of the ADC Input Circuit time to reach 1/4 of the LSB. The ADC has 12 bits. I also know that C=12 pF and R=10 kohm. I found a formula that i used ...
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### How do I work out the time when given current in a RC circuit?

So this exam question looked straight forward, but I can't get the right answer. I'm trying to find the time, from when the switch is close,that the current will equal 2mA. I've used a few formulas ...
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### Unexpected sinusoidal wave at low voltage setting on oscilloscope?

I'm fairly new to electronics in general, and I'm learning to use an oscilloscope. I have a 10X probe attached to a 1uF capacitor that is completely discharged. When I set the time interval on the o-...
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### Delayed Overcurrent Protection

I trying to find a solution for a problem that I have with a system I am responsible for. The system runs on radio control, the problem we had is one of the radios got stuck on transmit and blocked up ...
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### Measuring time using an STM32F407VGT6 microcontroller

I'm using a custom board for charging and testing batteries. Its 'brain' is an STM32F407VGT6 microcontroller. I'm developing in Ubuntu (14.04.2 LTS), using ChibiStudio (ChibiOS/RT 3.0 development ...
157 views

### Lengthening charging time of a capacitor

Alright, so I got a circuit that charges a capacitor and I want to charge it to a fixed voltage in a longer time than than the current provided would have (as the current provided would have charged ...
14k views

### How long will this appliance run from a battery?

How long can I run a water pump which requires 12V and 50W from a 12V, 40Ah, 400A car battery? Can you explain how this was calculated?
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### Proof: A strictly bandlimited signal must also be a signal of infinite time duration [duplicate]

How can I show that a bandlimited signal is also of infinite time duration? I know it has to do with Fourier transforms and convolution but I'm not sure how to actually prove it. I also know that the ...
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### Getting frequency of a signal from its phase

How Can I get the real time frequency of a signal from its encoder phase angle. The encoder gives us a triangular wave from (0-2*pi). If I use derivation, I get discontinuity which provoke spikes. ...
3k views

### How do you find the voltage across a capacitor at time t= 0 and t = infinity?

Here is a diagram of the circuit, I am confused about problems a and b. How do I go about solving these two problems? Thanks! By the way you don't have to tell me the answer, I just want to ...
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### Ä°s this system is a LTI or not ?

I have a F system and a input of this system is e x(n) = e^iÏ€n/4 and output is y(n)=cos(Ï€n/4) So is the F system is LTI or it would be ? I try to using addivity and Homogeneity but I cant do it
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### What kind of time delay switch to choose to reverse motor for just a couple of seconds

I would like to know the following: I have a motor driving a lead screw which transports a part either up or down. When going down and something comes in the way a switch gets triggered by the ...
627 views

### Shortest time required UART- UART transfer of 32 Byte block

I need to transfer 32 Byte block UART to UART 8 clock cycles per bit 1 start bit Struct 8-E-2 8bits 1 UART char, Even Parity, 2 stop bits/ char 1 + 8 + Even parity + 2 stop bits = 11 efficiency = 8/...
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### Do LED and photodiode rise times matter for time-of-flight (TOF) measurement?

Do I need small rise times of an LED and a photodiode/APD when considering time-of-flight measurement? Given I know rise time of both diodes I am always able to count time of flight by subtracting ...
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### What's the thermal time constant/capacitance of a 1/4W resistor?

I can't find it anywhere, what is the thermal time constant or thermal capacitance of a standard discrete 1/2W resistor? A table with other resistors of different power ratings would be nice, too.
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### Transient analysis of filters inside allowed band

I understand that a zone pass filter will cut off portions of the signal in the cutoff zone, and allow or amplify the frequency parts of the signal in the allowed zone. Now lets assume a signal that ...
264 views

### How to calculate average delay time of circuit having several possible transition states

Is it possible to calculate average delay for all possible states directly without calculating them individually using Xilinx or with Cadence.
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### Synchronized pulse generation from wirelessly connected boards

I want two or more boards (less than 10m range) to generate a LED blink at same time, within 1 ms difference, using wireless communication. First, due to power consumption, I am thinking to use ...
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### How long will it take to completely run out of power a Li-ion battery of 3.7V and 1000mAh, if the load consumes 16mA?

I'm trying to determine the exact time that run out power a Li-ion battery of 3.7V and 1000mAh. I'm using a load of 16mA. If I use the theoretical calculus: time=\frac{1000mAh}{16mA} = 62.5 \;...
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### Anyone have specific examples of how IEEE 1588 is most commonly used in industry?

I've run into the concept of IEEE 1588 synchronization over Ethernet several times, and am curious what its most common uses are and the details of why it is required. For example, I read that cell ...
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### How is time of supplied real time clock module maintained without battery?

I am thinking about purchasing this RTC ( real time clock ) module. Since this particular item comes supplied without a battery, I wonder how the time is being kept running in the chip since it's ...
496 views

### Determining Pipeline Cycle Time

I'm having trouble figuring out how the longest stage of a pipeline is calculated given the following: "Your processor has a 3-stage pipeline where the delay is 26ns through the first stage, 40ns ...
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### How many devices can I power?

I have a device that requires 1.21 Gigawatts over one second to fully activate. Upon activation the device is disconnected automatically. The device can accept the power at any voltage, and will ...
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### Electromotive force and Faraday's law

If Faraday's law states that Emf is inversely proportional to time, how is it that we can give emf in the unit volts? I'm a second year electrical apprentice, so am I missing some sort of relationship ...
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### Wirelessly get the current date and time

I know there is a wireless signal all over the US (at least) sending out the current date and time. Some clocks use it so they don't need set, just not sure what its called. Is there a module or a ...
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### What determines the communication speed? is it the physical link's speed or the communication card speed?

Two IEDs (Intelligent Electronic Device),an electronic relay and a gateway, are connected with Modbus RTU protocol over RS232. In the relay's manual it states that a speed of 9200 bauds can be ...