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H: Converting 3 seperate 4.5V battery operated devices to one AC power supply I'm wanting to convert 3 battery operated marquee signs to AC power by following one of the many tutorials out there on sites like instructables.com. I'm more than capable of doing each one on its own and having 3 wall warts for each sign. ...
H: DC to AC converter I know there are lots of circuits that do this, but I need to design a circuit that has a DC input and a square wave output by using any of these components: capacitors, inductors, OpAmps, resistors, diodes, and a dc power supply To be more specific, the square wave should have a duty cycle of 2...
H: Why is XNOR gate not referred to as an "Equality" gate? I am a programmer and I was thinking about some logic I was just writing and the logical statement started out as a negated exclusive or, but this simplifies to a logical equality check, e.g. var x = a == b. That is to say, we can express this as x <- a XNOR b...
H: Making my own Breakout board for a GPS I am prototyping a few things and wanted to make my own breakout for something that I haven't done before: GPS. (link to page) I know that high-freq. PCB are usually different compared to regular PCB. My question to you guys are as follows: Is the ground plane nessecary? Sho...
H: Are these PCB , and if so can it be repaired? I'm very new to soldering, and I think I have irreversibly damaged the circuit I was trying to fix. The joints are pretty burnt, but I read that in some cases you can scrape the carbon off and get a workable joint. I'd very much like to know if I can save my circuit by...
H: Finding the correct wire I am trying to connect my apartment door bell system to my raspberry pi; I am not too good with the wiring, and hope someone can help. What I have: 3 wires from the door bell system: red wire, black wire, white wire. 1 digital multimeter 1 AC/DC to DC Power Supply Converter Step Down The...
H: How can I make a linearly tunable 50% duty astable multivibrator? I want to make an astable multivibrator with a 50% duty cycle that can be tuned with a potentiometer for generating sound, so accuracy is desired. My first thought was to build the standard one with transistors, but that requires 2 resistors that con...
H: How can an active rectifier block current? This is a 2 part question for my understand about how an MOSFET/IGBT based active rectifier controls current. 1) Assuming a 3 phase active front end to a DC bus, and some huge load on the DC bus attempted drawn below. (Only 1 phase drawn, ignore exact values) simulate th...
H: Does the 802.3 Ethernet standard provide a recommended circuit design? I have a project I am designing whose fundamental parts consist of sensors connected to a micro-controller. the micro-controller will then send the data out over an ethernet port using standard tcp/ip protocols. I have already created the a proo...
H: What is the pin to light up colon in Basys 2? I am trying to make a clock in a Basys2 board but I can't find in documentation the pin to light up the colon of the 7segment display. Where is it? AI: I don't think the colon lights up. From reading the schematic, in page 2 you can see that there are 12 wires, none of...
H: Why can't I measure resistance when there is current on the potentiometer? Probably a very basic question but I have no idea why this happens. I have a 1K potentiometer. When I measure the resistance over its legs when it is not connected to anything, the results are as expected and alter expectedly when I move the...
H: what i have to use to only allow voltages above certin value to pass? I have a school project which it requires me to design a logical circuit that tests a 12v battery if it is full or not or half-full and light the corresponding LED, but, I am having a trouble because I want a component that only allow a voltage t...
H: Why can sticking fingers in an electric outlet kill you? I just wanted to learn some differences between volts, amps, ohms and so forth and came up with this question. If your skin has 100k ohms resistance and the outlet is 220v wouldn't the current flowing through your body be 0.0022 amps? AI: In Europe the rule i...
H: How to delay a "not gate oscillator" to make it run at a desired frequency? I want to blink an led(0.75 seconds on and 0.75 seconds off) repeatedly. I was thinking of using an idea from a book called "But How Do It Know" by J. Clark Scott. A part of the book tries to explain how to make an oscillator to use in a co...
H: How to work to find the values of the components that should be used in a project My question is somewhat general but I will try to narrow it down. I want to build a project for which I have all the necessary components and the knowledge as to how I should connect them but I don't know what their values should be....
H: How can a GPIO logic to high amp/voltage logic adapter be built using multiple voltages? (5v, 12v, 24v) I'm working on a project that requires making a fairly universal board (to work on different model machines). I need to hook up many pre existing motors and switches/sensors to the board that all work off of dif...
H: Paralel charging two Lithium Polymer batteries on a MP3 player Colorfly C4 Is it a good idea to replace a built in lithium polymer battery rated: 3.7 V, 2000 mah with TWO x brand new 3.7 V, 1800 mah (much thinner stacking them together) connected in PARALLEL and place it in my mp3 player model (Colorfly C4)? As it ...
H: Using several microcontrollers as nodes in a neural network I recently read an EETimes article about Google's neural network experiment, where they used several processor cores as nodes in a neural network. That made me wonder: could it be possible to replicate this with off-the-shelf microcontrollers? I was thinki...
H: How to detect the duty cycle of a laser pointer Our assignment is to design an analog parking lot access system. A laser pointer will represent the car, and an ID detector will check if the laser's duty cycle is 20%. I designed the circuit that will give the laser an input voltage in the square waveform with a duty...
H: How to wire 3 phase motor to VFD I am trying to wire a new motor to a variable frequency drive (VFD) and having some trouble figuring out how to wire the motor to the VFD. The motor is a 1 HP, 3-phase, 208-230/460 volts, and I'm wiring a 120 VAC supply voltage into the VFD, which steps that up to 3-phase 230 V. I h...
H: Conformal Coating Affecting Inductor? Question: Could conformal coating affect the properties of an inductor by adhering to its windings? Context and problem: I have a simple boost regulator circuit based around the TPS61230 IC. It has a handful of SMD resistors and capacitors and one largish SMD inductor (http://...
H: Inductance changes in DC relay coils PWM operation of DC relay coils in order to save power while holding is now common. This is at a frequency that is high enough to avoid chattering or audible noise and low enough to not have to worry about switching losses or exotic circuitry. The in circuit coil inductance ca...
H: Subtract Diff-Signal (Millivolts range) on top of common mode voltage (volts) with opamp - very inaccurate I built a subtractor circuit as shown here with 10k each resistor. Now I want to measure current by using a shunt between the two inputs and letting a current flow through it, see here, figure 4, the only dif...
H: Surge protector helped me discover bad wiring at home -- neutral and line swapped; should I be concerned? I purchased two surge protectors and when I plugged them in at two different receptacles in my apartment, I noticed that the 'grounded' light did not illuminate on any of them. To shorten the story, I discovere...
H: Battery charge times I thought of an idea recently, and I wanted to know if electrical engineers agreed with my theory. I have a smartphone. Recently I bought a power bank because I found my phone's battery not holding up long enough. Now here is what I thought about while charging my power bank and my phone. If b...
H: Solid State Relay not working, am I mis-reading the data sheet? I purchased several IXYS CPC1017NTR SS relays from Mouser. I have 1.2v and .5mA of current running over the control input of this relay and the load side isn't connecting. Here's a diagram of what I'm trying to do roughly (I missed connecting the posit...
H: High frequency signal using low frequency micro-controller How do micro-controllers running at slow clock frequency (under 100 MHz) produce high frequency radio signal (2.4 GHz for example)? For example - ESP8266 runs on a clock speed of 80 MHz but is capable of wifi communication which requires a 2.4 GHz signal. A...
H: Why can't I blow a fuse? In the book I am reading, there is an experiment that consists of connecting an automotive style fuse and a 1.5V battery to observe blowing of a fuse. However my fuse does not blow. I have repeated the experiment with a 9V battery but still it doesn't work. After these results, I have tried...
H: Connect to "gold plate" connectors of existing PCB I got a Bluetooth heating thermostat that I want to modify. The board has an ATmega 169PA, and I identified JTAG and ISP "connectors". They all look like those five round golden plates in the upper right of picture. Their distance is about 2.54 mm (0.1 inch) betwee...
H: Auto power Arduino I'm working on that cool project that is power efficient . I'm working on a project that auto power the arduino at a given time and keep it on for less than a minute then it should switch off automatically too . I'm using an external circiut for sending a signal for the switching on purpose ( DS3...
H: How many SMD 5630 LEDs can I power with 12V 1A power supply? I am new to this and have what is probably a newbie question. I am using SMD 5630 LEDs from a strip that I am cutting off and wiring each LED individually. They will be wired in parallel and I am trying to understand how many I can power with a 12V 1A po...
H: Micro controller programming with bluetooth dongle I have this USB bluetooth dongle . I want to know is it posible to active this dongle with PIC 16F628a micro controller and communicate with PC. I know this micro controller support serial communication, but I don't know is this application is posible. Thanks. AI: ...
H: Power of piecewise defined signal Here is my task: Periodical signal is given (only one period of signal is shown): Calculate value of voltage K so that average power of this signal equals 1.5W. Power of signal can be calculated as $$P=\int_{0}^{T}u^{2}(t)dt$$. My idea is to express u(t) and solve equation $$\int_...
H: 5w resistor circuit and increasing circuit speakers power I am new to electronics, and I am working on an amplifier circuit that contain LM386. This is the schema of it with bill of materials: Does this circuit give a huge sound ? If not, do I need to increase speakers "W" or I need to make changes with circuits...
H: LTSpice Simulation Showing Inaccurate Results and Excessive Current So I'm trying to make the following simulation work properly to verify some hand solving for a circuit. The circuit is an LC tank with some diode clamping, and an initial capacitor voltage of -50V. I tried both with and without a switch to see if ...
H: ATMega2560 timer not increasing again after overflow I want to generate waveform with f = 196 Hz using only normal mode. Here is the code I use. Whenever the timer overflows TOV1 is set and PIND0 will toggle. TOV1 is cleared after that and I wait for another overflown to happen so PIND0 will toggle again. I tried ...
H: PWM created from 16-bit timer and 32-bit timer I have a question that does the PWM created from 16-bit timer differ from one created from 32-bit timer. Personally, I deem that they are the same, since by taking the fourier series of the PWM signal I see that the dc level of PWM signal solely depends on the duty cy...
H: What power source and amplifier should I use for high reactive power purpose? I searched the site but most I can find are questions on what reactive power is! I want to know how it affects my decision for the power supply. I have to drive a coil (AC) with a high reactive power (1 kVAR) and little real power (20 W)....
H: How does this string of LEDs work? I bought a cheap string of LEDs in the supermarket (the christmas decorationny type) and just out of curiosity I'm trying to figure out how it works, because I can't understand how it doesn't short itself. It consists of a basic holder for two AA batteries with an on/off switch, a...
H: Is the laptop's power adapter output negative terminal grounded? Today I find my lenovo laptop power adapter's output negative terminal is not grounded (the input ground terminal is not connected with output negative terminal, measured with DMM). But another old one is just opposite, the output grounded. Why? There...
H: Can I replace a 27.12MHZ by a 13.56MHZ Xtal on PN532 I have a prototype of NFC reader which is attached to my Board. But it seem it doesn't work ... the only change I made was the Xtal because I don't find 27.12MHZ. Some people told me I can replace it if the hz was a multiple. The fact it don't work as expect. Is ...
H: Powering multiple white LEDs in parallel Recently the idea struck my mind, that I wanted to build a simple but useful emergency light which can run off of any USB port (the specific use case would be to power it from an USB power bank). For that I wanted to design a simple circuit that drives 25 white LEDs (3.2 V, ...
H: Need help to design a reverse mosfet/transistor switch I have an accelerometer kind of sensor which gives analog voltage at level of uV-mVs. I want to read voltage values from it with a MCU. I am expecting it will not give more than 0.2 V in normal conditions. So I designed an amplifier where 0.2 V gives 3.3 V at t...
H: Power an LED strip, power supply or transformer? I'm new to electricity so don't judge me too much. I need to power 5 watts of led strip. Is there a difference between a power supply and a transformer? I found a transformer in my local hardware store and it says: connecting power 10-50 watts, can I use it to power ...
H: What is difference between choosing OCRnA and ICRn in timer/counter CTC mode in ATMega2560? I can't find any difference since both function the same role: define the top value so that timer will reset when reach this value. Both have its interrupt flag and interrupt service routine. AI: The difference is that choos...
H: "error #28: expression must have a constant value" - with nRF51822 app_twi I have been attempting to copy the nRF51822 app_twi example for own application in order to get a better understanding of how the HAL works. However, now I have an error now that I don't understand since my code is basically identical to the...
H: Inductive reactance: frequency vs current. Why current goes to zero as frequency increases? Suppose I have the circuit below with the frequency of the voltage source as a free parameter. Assuming the inductance is constant, the current flowing through the circuit shoud equal $$I(f) = \frac{V}{j2\pi fL + R}$$ (I'm ...
H: Through board connector I'm looking for a connector. Ideally it would be a one pin connector mounted on the back side of a board and the pin would come through the board into connector. Here's an illustration: Does such a thing exist? And if so what's its name and where can I buy one (or actually about a hundred)....
H: How to pick capacitor dimensions What are the tradeoffs and design considerations for capacitor dimensions? Specifically, I need to select 2 electrolytic capacitors (C2 and C3) for a car voltage (noisy 12V) to 5V converter. Here's the circuit: How would I pick a capacitor from this datasheet? http://www.mouser.com...
H: Triggering BT139 Triac from Microcontroller Using 4n35 Optocoupler This is my first time posting on a forum so please pardon me if i do anything incorrectly. I'm kinda new with using TRIACs, i'm using them as a replacement for a Relay and my sole goal is to switch a light bulb on and off from an arduino. I'm havin...
H: Timing Issues with Optically Isolated Data Signal I have been working on a system that requires data transmission between two devices powered by separate supplies. I have based my design on the MIDI-hardware Spec, as I'm comfortable working with that configuration and have successfully implemented it in other areas...
H: multilevel storage elements I've been experimenting with three-valued logic (yeah, I know) and have had quite a bit of success by using voltage comparators to implement the combinatorial logic. All 27 1-input gates and many useful 2-input gates are functioning as expected. The progress is documented at https://hack...
H: 555 Timer in Bistable Mode - Unexpected Behavior When Removing Power I have a question regarding a 555 timer (TLC555CP) in bistable mode. Here is the schematic for the circuit in question. Now, this circuit works as I expect, when I hit the push button attached to the trigger the led goes on and stays on, and then...
H: Given a transfer function i want an op amp represantation I have a project for my university on the transfer function (where a,b,c are constants): $$G(s)=\frac{(s+a)}{(s^2+bs+c)}$$ and I'm asking how to represent this whole thing with an OPAmp circuit. (The difficult part that got me the most time thinking, is the...
H: convert 5v AC to 3.3 DC I'm working on my raspberry pi door bell and facing the electricity problems that is beyond my knowledge, please help What I have: one AC wire from door bell, it's around 0V when Idle, then when someone press the door bell button, it increases to 5V AC What I want to achieve: My RPi needs th...
H: the voltage resolution for an analog signal with an amplitude say,i have 16-bit DAQ that can read at a rate of 250kSamples/second. What is the voltage resolution for an analog signal with a 2V amplitude? For what value of signal frequency can I safely digitize this signal? How can we relate bit daq and samplas/seco...
H: Controlling 64 stepper motors with arduino I have seen many post on this site for controlling stepper motor with arduino. And arduino is pretty good at it if provide with good shield/Driver. My query is How can is use to arduino control more than 2 stepper motors i.e(64 stepper motor). It seems to be a huge project...
H: Is this memory card circuit designed properly I'm looking to build a reusable memory card for my SRAM as the cost of the chips can get up there. I'd like to be able to plug this into other projects (mainly with a W65C816S as I work with it) both with a breadboard and other PCBs. Before I go about laying this down o...
H: How is the solution for \$\alpha\$ and \$\beta\$ current gain of a BJT derived? I'm just an enthusiast, and not too good at maths; I'm exploring constant current source circuits, in doing so I came across two equations for BJT current gain: Could someone help me understand how \$\alpha\$ and \$\beta\$ are derived t...
H: multiple motor h bridge? I see a lot of h bridge diagrams on the internet, more or less like this: If I wanted to connect let's say 4 motors in h bridge configuration while using the same power supply (12v) for all 4 of them and would also like each motor to be able to work independently, what do I need to do? Is ...
H: How to set SD card clock frequency between 100 kHz - 400 kHz I am interfacing a 32 GB microSD card with PIC32MX795F512L. I am following the examples provided in Lucio de Jasio's book. As the author has described that to set a 250 kHz, they are driving their peripheral clock frequency by 144. Which means 36 MHz when...
H: Good fan speed for solder fumes I am going to be soldering in an enclosed space, so I am building a fume extractor via ducts. My eventual plan is to have one fan near the vent, and another somewhere near the inlet to help the fumes get to the ducts. So my question is how powerful should the first fan be, preferably...
H: What is the way to detect SD card insertion/removal? I am interfacing a 32 GB Micro SD card with a PIC32MX795F512L. I am following the examples provided in Lucio de Jasio book. In one of their example, they are using while( !getCD()); to check if the card is present or not, but this doesn't seem to work in my case,...
H: Is it possible to pick up noise in an audio circuit through the ground / earth wire? In an audio circuit, such as a guitar's electronics (the only thing I ever dabble with!), I have always thought (probably simplistically) of every point along a continuous earth path being essentially all at the same voltage (a 'ze...
H: PWM and DC motor speed I'm hoping to try to control the rpm of a DC motor. AFAIK, I'd need to generate PWM for that. How does one find out which frequency is needed for a certain rpm? Is the frequency of the PWM signal supposed to be related to the speed of the motor? Thanks AI: The idea of the PWM speed control of...
H: TFT LCD interface I am little confused in basic understanding of LCD interface. Many times datasheet suggest 8/16 bits MPU interfacing. Here, for interface we assign GPIO's of microcontroller to respective data pins of TFT ( DB0 to DB7 or DB0 to DB15 depending upon 8/16 bits interface ) Sometimes in TFT datasheet, ...
H: What happens to a Sine wave in the frequency domain? Say for eg.if we have a sinusoidal signal of f = 1KHZ, VPP = 1V and Voffset = 0V If I change my Offset Voltage from 0v to +5 V, What would be the effects in Time domain and frequency domain? AI: You will see a single peak at 1KHz. In the frequency domain, in...
H: How to blink LED with 1.8V? I am experimenting with an Intel Edison mini breakout board with pinout like here: http://fab-lab.eu/wp-content/uploads/2014/10/Edison_IO_LED.jpg Now, I soldered header pins to plug the board into a breadboard. Unfortunately, the GPIO levels are only 1.8V. What should I do to make a LED...
H: BJT Saturation with small load/ H-bridge I am trying to analyze the operation of a BJT H-bridge configuration. I have searched through these forums and Google and can't seem to find an answer to my question. It is my understanding that it would be desirable to have the "ON" transistors in the saturated state, to p...
H: Impedance matching resistor for ws2811? I want to design a circuit using ws2811 on page 5 of the datasheet It says "To prevent the reflection and hot-swap protection, we suggest to connect a 33ohm resistor at the data input or output port for impedance." But on modules and boards on the market I don't see these 33...
H: Forced beta too small Let's take an example in which the recommended beta for a transistor's(NPN) saturation is 10.If you use a forced beta smaller than 10,will the transistor still be saturated succesfully?Can hFE be small enough to damage the BJT? AI: If you use a forced beta smaller than 10,will the transistor s...
H: adjustable IGBT current? Goodmorning all, Here my very first question so I may be asking something that is may be already answerd but I couldn't find, My question is : How is current limiting achieved in modern IGBT based welding equipment? I do have a DC TIG welder myself and I am just curious how to achieve a max...
H: TVS diode electrical parameters I am using below diode in my design to protect 3V3 lines:- http://www.ibselectronics.com/ibsstore/datasheet/AZ5123-01F_Datasheet.pdf On page 2 they have given :- Also, they have given on same page :- What is the meaning of this!! What is +-16KV & what is the 7V?? AI: They are sayin...
H: Small switch with a button top for gliding over? I wonder if there's a kind of switch for low voltage devices (~3V) that allows small nipples to glide over. For instance, I have a small plastic rod with small nipples (~1-2mm high) and I'd like to count the number of nipples glided over the switch position. I've loo...
H: What is the intended use of high current SSRs and triacs? I answered a question recently regarding power dissipation in solid state relays. This is the calculation: Consider this 40 A rated triac - BTA40. Vto = Threshold voltage = 0.85V = Voltage drop across triac. Rd = Dynamic resistance = 10 mohm Assume IT(RMS) ...
H: Multiple Broken Relays -- What About My Circuit Is Making Them Fail? I recently purchased one of these relay boards ... to use along with my Raspberry Pi to switch an AC outlet on/off to control a fountain pump. Since the relay board requires 5V for the control lines and needs to pull more current (IIRC) than the...
H: Easiest way to generate 25V speaker signal I have a fire alarm that accepts a 25v line level speaker input at 4w, what is going to be the easiest way to play arbitrary signals over it i.e. from a 3.5mm jack, an amplifier and a transformer? are there small pre built modules for this purpose? Everything I see seems l...
H: Why would a 150 MHz probe work fine for a 100 MHz oscilloscope? I read in many forums that one can use a probe with a higher bandwidth than oscilloscope's bandwidth. If it is right why it is not a problem? What is the theoretical explanation? AI: That is right. Not a problem in doing that. Think of it as a filter ...
H: Sony STR DN1030 2nd volume control using a second Vr Encoder First off, I am very, very new to any electronic physics/engineering. Here's my problem: I want a second remote volume control for my receiver that is wired to my desk. (I have already managed to make the standby switch work) There are three pins on the c...
H: Do I need special charger for a Lithium-Ion battery? I want to use a Lithium Ion Battery. I saw that there is also a different kind of chargers like Adafruit Micro Lipo/MicroUSB or Adafruit Micro USB Lipo for this kind of battery, do I need it? Can I charge my battery direct from a voltage source? AI: As mkeith men...
H: How to program multiple STM32Fs on same PCB I work in a management roll and only have a very limited electronics knowledge (enough to make simple arduino projects etc). We are working on a product at the moment which has 3 STM32F303s and 2 STM32F103s and the main processor being a AM5718. I was just wondering how y...
H: Why am I getting very different measurement results on a breadboard? I have an AC to DC multiple output adapter. It has the following output: I set the voltage to 5V. When I measure the supplied current, I get 3.26A. Then I connect an output to it: When I measure the supplied current now, I get 3.23A. Then I try ...
H: Energy wastage in wireless charging rotary toothbrushes? I'm not going to change my habits based on the answer, but I did wonder from a theoretical standpoint. I get idea of wireless charging. I still have flashbacks to my power generation & electric motor courses in undergrad (3 phase systems, lossy magnetic field...
H: Do buck converters increase the ampere hours of a battery? I've read that they are 90% efficient compared to linear regulators so given the relationship between volts and amperes and that I want to power the project off of a 12V battery that has 18Ah and is charged using a small solar cell. The project itself only ...
H: Review my PCB? Mosfet to parallel leds Can someone please review my PCB? Simply, I'm running 24 IR Leds at medium power, from a 5v arduino MCU pin, all pulsing together (38khz). Big fat traces, lots of space, SMD components. The LEDS are in 8 3-serial runs, and I have power/ground traces around. The "leds" on t...
H: What is the transfer function of an LCL filter? simulate this circuit – Schematic created using CircuitLab I read that for grid-tied inverters it is common to use a LCL filter like above, to turn the PWM output from the H-bridge into a sine. But I'm having trouble designing something like this. If you'd calculate...
H: Measurement of negative DC voltage I want to measure -30Vdc up to 0Vdc using a microcontroller. I'm basically measuring a voltage source with an output current of upto 2A. I need to bring the voltage up onto a scale of 0V to 5V so that I can use the ADC of my microcontroller. I found two types of solutions to do t...
H: Does my PCB require a 50 ohm impedance trace even if I am using an external antenna? I am using the Quectel M95 GPRS Modem on my PCB. The hardware reference guide says "pin 39 is the RF antenna pad. The RF interface has an impedance of 50Ω." I am using a u.efl connector and connecting a QuadBand PCB antenna to the ...
H: Is voltage measurement of a battery done in series? This might be a stupid question but I can't find an explanation. Voltage measurement is done in parallel. But when we measure the voltage of a stand alone voltage source, say a battery, it looks like we are doing it in series and yet we get the correct reading. s...
H: Trying to remove distortion of speakers seems impossible I'm working in a project with the goal of make a portable bluetooth speakers without distortion. When I try to turn up the volume, the speakers start to make a distorsion, like when rhe radio can't get the correct frequency.p In the project, I use a 3×2 PAM84...
H: Correct way to measure a wall wart voltage I got a full drawer of second hand wall warts which I'm planning to use for powering arduino projects (mostly 5V "pro mini" or "nano"). I'm using a voltmeter to check that they are still working, however most of them seem to output a far greater voltage than what is printe...
H: Adding antenna gain to RX and TX sensitivity Let's say I have a transceiver with 10dBm of TX gain, and an RX sensitivity of -10dBm. If I then attach an antenna with a gain of -2dBi do I then have an RF output power of 8dBm and an RX sensitivity of -8dBm? I'm not clear on if I have to flip the sign when adding t...
H: Mains LED light bulb flickers when switched off We have LED bulbs in our apartment. In the bathroom, the bulb flickers on and off when it's switched off. Same when it was a CFL bulb before I switched to LED cause I hate CFLs. Our mains voltage is 220v. The bulb we have looks like this If I remember correctly, I sh...
H: Implementing/using a SATA controller I start by saying that I'm not an electrical engineer, I've got a basic understanding of things from school and from work (I'm a long time computer programmer), but this is not much my field of competence. I'm in the process of evaluating the feasibility of a device that I'd lik...
H: Protection of a 1.2V bus I typically put a TVS diode on all of my power rails as standard practice to protect against ESD events. I'm using an FPGA in a design for the first time and I'm finding that I can't get a TVS with a 1.2V reverse standoff voltage to protect the FPGA core voltage. The only close options I co...
H: Why should the output impedance of a current source be much greater than the input impedance of the load? For a voltage source (except RF circuits), the output impedance of the source signal being coupled must be much smaller than the input impedance of the load. This is first of all done to prevent loading. Also ...
H: Storing images for LCD For TFT LCD, if we want to store images for displaying on screen..can we use flash IC for eg: SST25VF020_2Mbit serial(SPI) flash. Please someone guide since I am newbie to TFT LCD interface. Thanks. AI: You can use any form of storage to recall your images. But define an 'image'. Yes; the end...
H: MOSFET Circuit Design and Thermal Considerations I'm a newbie at EE, and just I wanted to verify that the design I came up with for a MOSFET circuit that drives a 12V 500mA water pump will work. I'd also like to confirm I can run the N-Channel MOSFET in question (RUR020N02) without a heatsink. P8 is a two-pole ter...
H: How can I mirror a group of components and wires across a line in eagle, without having it switch board sides? I want to design a board that is symmetrical - I have designed the left side, and now I want to copy the components and wires to the right side such that it is "mirrored" across the center line - what is t...
H: Transformer VA Ratings, Power factor, and Pulsed current What exactly goes into a transformer's VA rating? At a fundamental level it seems that there has to be a limit to what the VA rating can represent. For example if I draw 2 Amps-RMS from the secondary of a 30VA rated transformer at 15 Vrms this makes sense as ...