# All Questions

119,273 questions
57 views

### Cat6 Ethernet connections

I have been trying to create my own CAT6 cable lengths, but have been having problems with achieving a connection. Every diagram that I have seen online doesn't match my wires exactly. I have an ...
33 views

### Direct coupling Biasing of Two stage amp

General question. I see a lot of two stage amplifiers with a diff pair input and a cs second stage. In IC design these two stages are always directly coupled ie. the dc bias of the second stage is fed ...
174 views

### Why so much variance in the continuity beeper threshold? How do these beepers work anyway?

In this answer it is mentioned that the EEVBlog-branded BM235 meter has a threshold of between 30 and 480 ohms for its continuity beeper (as seen on page 25 of the datasheet). My first thought was "...
50 views

### LD1117V33 voltage regulator heatsink, thermal paste needed?

I want to screw a heatsink to my LD1117V33 voltage regulator. It's a normal 3mm screw and nothing inbetween. Do I need to use thermal paste or something like that? It will be regulating 12V down to 3....
52 views

### Manually place a few vias in Altium

I placed a few vias manually. I get "Un-Routed Net Constraint." How can I fix that?
26 views

### Voltage cut-off in FDC6331L

I've prepared a circuit which allows to cut out the voltage. It is based on an FDC6331L IC. My circuit is as follows: E_GPA6 is an I/O pin from an MCP23017 ...
99 views

### Why does this resistor get ignored in the calculation of voltage across the capacitor

I am trying to follow this example problem: I understand the current calculation. What I dont understand is why the 5 kOhm resistors voltage drop does not need to be taken into account when finding ...
71 views

### Resistance between non-inverting input of op-amp and voltage source

I encounter quite often this sort of problem in my textbook: This is a classical non-inverting op-amp. However, I'm always perplexed with resistance R1 between voltage source and non-inverting input. ...
35 views

### How does one calculate output voltage noise of a current output DAC?

I am using a current output DAC connected to a voltage reference and a transimpedance amplifier. I know the noise characteristics of the voltage reference and the amplifier. The DAC simply lists "13 ...
61 views

### Why my circuit only draws max. of 2.8V across the electromagnet? (Circuit picture included)

I created a circuit using Arduino Uno and the goal is to use pulse width modulation (PWM) so the voltage across the electromagnet decreases from maximum value to zero, and then the cycle repeats. The ...
38 views

### Vias stitching problem in altium

I need to create a VIA stitching on net M4- but the option doesn't work.
85 views

### Clamp multimeter RMS current measurement, AC versus DC confusion

This question doesn't relate to a specific meter, I am using AMPROBE AMP-220 manufactured by Beha-Amprobe. I believe am an experienced engineer but only in the digital world, not really in power and ...
90 views

### Wiring Diagram Explaination

Can someone please explain the notations used in this wiring diagram and how this is configured. I am looking for only right hand end of the circuit.
43 views

### Electronic load for negative voltage PSU

I am making a MOSFET based electronic load to test my PSU rails. Below is a simplified version of my circuit with V2 as the PSU that is being tested. I want to be able to test negative voltage rails ...
54 views

### 3v to 7kv boost step-up circuit drawing [on hold]

I don't know if this is the right place to ask this, but would anyone be able to draw a circuit for this boost step-up: https://www.amazon.co.uk/7000V-Step-up-Module-High-voltage-Generator/dp/...
34 views

### How to calculate small signal parameter for a BJT when early voltage is taken into consideration?

I have proved one formula of output impedance ro = (Va+Vce)/Ic = Va/Ic' where Ic is collector current and Ic' is collector current neglecting early effect. But reading from standard texts other ...
36 views

### Delay between SPI CS and clock on beaglebone

I want to send some data to a micro controller with a beaglebone black (beagle bone is master). As shown in the picture, the delay between falling edge of CS and first rising edge of clock is too much....
46 views

### DUE schematic doubt Altium

I have the schematic of Arduino DUE for EAGLE software, I found a part I dont know what means for Altium Software. Can somebody tell me what is it "ETH" ? A header?? Arduino Due schematic I found ...
16 views

### CH1817 ring detector square wave to low

I have a project, trying to make an old rotary phone work with a new touch tone voip service. S far the dial inputs and dtmf outputs with an arudino. My next step is the ring detector circuit. I have ...
29 views

### How to power a device with a LIPO battery correctly

I have a little device which is normally powered by 5V 2A. But the manufacturer says it is compatible up to 16V 2A and I tested it with a powerbank which outputs 12V 2A. Sadly this powerbank is a bit ...
81 views

### Output capacitor in LDO regulator

I want to use an Analog Devices LDO regulator (ADP7104ARDZ-5v.) When I checked the datasheet, I found out that it requires just a 1uF capacitor on the output pin. Then I searched more and I found an ...
19 views

### uc1609 LCD driver

How to connect LCD Display HEM19264-05 with UC1609C LCD driver to stm32l476g-disco? I'm confused by the UC1609C. I could not find any datasheet on UC1609C. There are unusual pins. I found just pinout ...
14 views

### The connector circuitory for APD connection with simulating systems

I have an 230-8 series avalanche photodetector which is to be fed with high reverse bias. What mediator circuit will be required to get the signal onto my system on LabView platform? Where can I buy ...
1k views

### Is the continuity test limit resistance of a multimeter standard?

The continuity shows us the shorts, but many times I guess, even if the wire has a resistance of up to 50 ohm, the continuity will beep to indicate a short. Is it always 50 ohm, or what parameter ...
25 views

### Building Micro Switch Circuit for Air Conditioning

We want to build a microswitch using a contactor and a timer from a loq voltage signal The scheme is, Door Contact - Contactor - Timer - Turn the AC Off The contactor im planning to use is this, ...
97 views

### STM32 MCU gets shorted

I've been trying to make a simple audio player using the STM32F302CBT6, however, the VCC and GND pins of the MCU keeps on getting internally shorted when a 3.3V power supply is provided and a faint ...
58 views

### RE)))) Full adder by using two 2x4 decoder [on hold]

How do I draw "Full adder using by two 2x4 decoder" Please solve that problem. ++ And I solved that problem by using my brain. But I don't even know that is true. My answer is right?
38 views

### Antenna mounting confusion from Datasheet

I ordered a few samples of a particular antenna, because of the datasheet showed a rather peculiar layout - so I wanted to see what the actual component is and how it performs. Antenna is Abracon's ...
105 views

### What happens if a part uses more current than the regulator is rated for? [on hold]

I want to use a 5 volt regulator to regulate a circuit's voltage and the regulator is rated for 1.5 amps. If my circuit would use more than 1.5 amps, would the regulator just not supply it or would ...
22 views

### mcp2221 i2c CLOCK down after ACK

I am trying to control an Analog Devices programming resistor AD5254 by a USB to I2C master device from MicroChip MCP2221. The problem I am facing is that each time MCP2221 is waiting for ACK from ...
40 views

### Passive PA resistor came loose

I need some help! I have an Australian Audio XRS12 speaker. After a gig I heard something rattling around inside the cabinet. I opened it up to find an 8 ohm resistor that had come loose. It looks ...
53 views

You have a 500kVA load with a power factor of 0.6 lag. You add an additional synchronous motor with an input of 80kW and max power factor of 0.8 leading. Determine the reactive power and the overall ...
19 views

### How to count the gate voltage and drain current from the forward transconductance value?

How do i get the ratio of Vgate/Idrain according to the value of the forward transconductance in the MOSFET data sheet? The units i got is 6 siemens, but i don't ...
2k views

### Mathematically modelling RC circuit with a linear input

I have found a plenty of documents and books that model how the voltage across a capacitor behaves within a transient RC circuit, using the following equation: $$V_C=V_{MAX}(1-e^{-t/RC})$$ ...
99 views

### LM555CN drawing too much current [on hold]

I want to use 555 timer with a DC voltage Vcc of 12 volt to generate a square wave in astable mode but the IC draws near 90mA current at 6 volts only and gets heated up, I'm attaching the circuit ...
101 views

### Which arduino is inside the device [on hold]

I've got a few devices made using the arduino board. I was asked to update the program. However I've different version which must be used for different arduino boards. Is there a way to get to know ...
27 views

### help identify the SMD AK1629

Failed DVR Suspect that burned down this detail:prozvanivatsya short circuit in both sides can't understand which part to replace?
22 views

### Recessed Lighting Junction Box Cord [migrated]

A little while ago I bought some of the below recessed lights for the basement. Had an issue where one wasn't working so I punched a hole into the ceiling and pulled the junction box down, re-nutted ...
40 views

### STM32 Reset Reason - detect debug reset

In my project I want to set the configuration of the RTC based on the reset source. If a reset is done via hardware reset NRST, the RTC shall be set to zero.If there was a reset due to wake up from ...
709 views

### Do I need to maintain source of a signal till it reaches the destination?

If I send a signal through a wire having delay of 10ms, then should I need to maintain the source of the signal till it reaches the destination or can I change after, say, 2ms and send the next signal....
45 views

### Designing a counter

I want to design a counter which doesn't increments value every rising clock pulse(assuming positive edge triggered). Say I have a FSM which has 4 states . Only after traversing of the 4 states , I ...
42 views

### CircuitLab simulation of 555 timer - OUT HIGH always delivering 5V irrespective of Vcc?

I've scratched together a design for a 555 timer based driver for an IR540 MOSFET. But in CircuitLab the simulator shows the 555's OUT voltage is always 5V when high, for Vcc ranges 3.3V through 24V. ...
48 views

### I'd like to run a 5v fan on 2 3.7v batteries

I have zero experience so if this is a stupid question please at least be kind. It seems obvious that I couldn't run the fan on one 3.7v battery but then I'm not an electronics guy. So I was thinking ...
13 views

### How do I save the values of Verilog Xilinx ISE Simulation? [on hold]

I have a Verilog simulation that essentially gives me 1024 samples of a signal, and I need these values in a text file. Could anyone tell me how to do this? I did look this up on the net, but I am ...
36 views

### 2-time constant (On + decay) timer circuit

Required is a timer circuit to switch on an LED with 2 time constants, when a switch is depressed as follows: when switch is closed, light an LED 10 ~ 20mA when switch is opened again, keep the LED ...
64 views

### Two server powersupplies in a row dangerous?

I have two server PSUs from HP which can output 12V with 1200W (HP DPS 1200.) My goal is to obtain 24V by chaining the outputs of the two units. I have modified one of the PSUs so that the negative ...
56 views

### What's the benefit of 24V over 12V in solar and charging?

What are all the benefits of 24V solar systems over 12V solar systems in regards to solar panels and battery charging? All I've been able to find is that you can use smaller gauge wire with 24V, ...
42 views

### Need a simple explanation of a left-right shift register

I'm familiar with basic shift registers. I'm having a hard time understanding the one below. I feel like I'm overthinking it due its complicated appearance. Would it be possible to direct me to a way ...