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H: How do contact type tachometers work?
In case of contact type tachometers we put the tip into a small hole in the rotating body. Sometimes there is a disc in the tachometer shaft that we touch with the surface of the rotating body. What is the science and logic behind this?
The picture attached below elaborates it.... |
H: External gate resistor calculation
I am trying to find external gate resistance value for my MOSFET.
Here are some details:
I am using IRFP4468PbF power hexfet mosfet - Datasheet
80V, 500mA, 3-Phase MOSFET Driver - Datasheet
I had worked out through some formula and found that
I=0.77A (using I= Qg/ Dt),
T= 702ns (... |
H: Extending solder only PCB pins
What is the recommended way to make solid connections to the pins below?
Can the soldering be avoided, and if not, what component should be used to provide the plug/unplug connection?
AI: Thanks all the guys that commented.
There seems not to be a solution that doesn't include solder... |
H: Convert TTL levels to RS232 of FTDI USB<->Serial
Have this small interface FTDI FT232RL to connect a Serial device to the computer via USB.
It has been working well for most of my Serial applications, except today when I tried to use it for a Roboteq controller. While all settings are correct, characters are garba... |
H: What makes E-bomb or Electromagnetic pulse (EMP) destructive?
wikipedia says that Electromagnetic pulse As with any electromagnetic signal, EMP energy may be transferred in any of four forms:
Electric field
Magnetic field
Electromagnetic radiation
Electrical conduction
https://en.wikipedia.org/wiki/Electromagneti... |
H: RTD Sensor Datasheet Details
I need to read one type of rtd sensor using linked datasheet(page5) but as far as i know there must be a temperature vs resistance table. Am i missing something or given datas are enough to read temperature. I will use 1 ma constant current. Thanks.
http://www.jumo.de/attachments/JUMO/... |
H: A question on voltage divider resistances used in BJT biasing
I'm reading a text on BJT common collector amplifier biasing.
Text says:
The voltage divider (R1 and R2) is used to give the input signal (after passing through the capacitor) a positive dc level or operating point (known as the
quiescent point).
The a... |
H: Can superimposed (combined) wireless signals create a health hazard?
Not to sound all tin-foil-hat-like but I'm learning about wireless signals and am trying to understand it better. So my question is:
When multiple wireless signals are transmitted at the same time on different frequencies, they end up getting sup... |
H: Minimum design for controlling 2 LEDs to light either one or both?
I am an absolute beginner in electronics. So far I have created a circuit with 2 LEDs and 2 SPST pushbuttons, each controlling a different LED. Very simple, you should get the idea without me drawing a circuit.
I've been trying to figure out how to ... |
H: Loop current of the loop containing a current source
I am currently studying circuit analysis methods and there is one thing regarding the Loop Current Method I do not fully understand.
Let us take a look on the loop current sketched below:
As far as I understand, in this method we will assign each loop a uniform ... |
H: Why float data type is not accurate on a STM32?
I'm using STM32F103C8T6 and my compiler is KEIL 5. I have written a simple program to check something but I found out an interesting point. When I download the program to the MCU, aaa and bbb have to be 12.56 and 62.8, but when I debug the program on the MCU, the init... |
H: The diode and the relay question
Do I need to use a diode with the following setup ? What i want to do is activate a relay which then closes the positive side of a nema 5-15 portable receptacle and allows electricity to flow. When a switch is pressed . My aim is to avoid having to come into contact with the AC and... |
H: Should I use an LP2953 to power an ATTiny85 with a 12v battery?
Like a lot of people I'm building a little transmitter unit with one of those cheap 433mhz transmitters and an ATTiny85, and I am having a problem with the power supply. Actually it is only the power supply, everything else works nicely. But my battery... |
H: SPICE Programs worth learning for
I was wondering what are the professional SPICE programs for simulating analog circuits in the industry now. For example, where the big companies like Atmel simulate their microcontrollers, or a company like Texas Instruments simulates their op amp design. Also, which programs you ... |
H: Common way of describing a "double-sided wait"
Is there a commonly used name to describe a "double-sided wait" data transfer protocol?
This is a uni-directional scheme in which data is transferred on the clock edge if both the sender and the receiver (alternatively called producer and consumer) indicate that they a... |
H: Need 300mA current to drive a transducer
I am working on a project in which I need to use a preloaded value to vibrate a transducer.
So loaded required values into Arduino Uno, converted into analog values using R-2R DAC and buffered values using ua741, all should work in 5 volts.
Now the problem comes:
I need aro... |
H: 60hz Astable 555 timer circuit not oscillating
Yet another electronics newbie here :)
I have tried to construct a simple 60Hz oscillator using a NE555 timer in astable mode, yet it does not seem to be oscillating. To test it, it has been connected to a speaker as I do not have access to an oscilloscope or any other... |
H: Why is the Tach output on computer fan referenced to the VCC?
I am working on an electronic field mill with a computer fan, and am following the design on this instructable.
The arduino needs to know what rate the fan is spinning to know when the shutters are open and closed to measure e-field voltage. We are using... |
H: calculate uptime of LPC1768
i want to calculate the uptime of LPC 1768 from when it begins running. for example a function like millis(); in arduino.
AI: I suggest that you setup a hardware timer that increments a counter every milisecond. By reading this value you will know your uptime. |
H: Phase Locked Loop: Confusion in Lock Range
For Phase locked loop (PLL), we can have two types of Phase Detectors (PD): Type-1 and Type-2. The Type-1 PD has an analogue multiplier (which is simply XOR for digital inputs) whose low pass filtered output is a signal which varies at a frequency equal to the difference... |
H: What is the general operating principle of an AC Electronic Load?
I'm working my way through electromagnetics and in particular power (line) transformers at the moment. I'd like to be able to run tests of various kinds at different AC loads and possibly at different frequencies, say 10Hz-10kHz, to observe frequency... |
H: Angles and measurement - PCB design help
I have started doing PCB design from last month and very new to this. I have done tiny bits on eagle cad and Altium cad but still learning things everyday. Now I got a challenging board to do. Though board is not complex but the measurements and angles has to be exact and n... |
H: Driving WS2811 LED strip from microcontroller
I'm planning to drive the input of a WS2811 based LED strip (total approx 450 LEDs) from a microcontroller/arduino, as per the diagram below.
Do I need a transistor, buffer or anything else between the microcontroller GPIO and the WS2811 DIN? Or can I safely hook it up ... |
H: When to use a heatsink for a voltage regulator?
Sometimes in small projects Im using voltage regulators with outputs 8V or 5V such as LM7805. Power is I*V but Im wondering when really a heatsink is needed. Sometimes the current flow from the regulator output is 1mA but in an other project 20mA or more. Is there a r... |
H: Multi-plex 8 BLDC motors using shift registers?
I want to drive 8 tiny diskmotors - they look like low current motors. robotshop 2mm vibrating disks
I want to drive perhaps 2 or three of them at a time with pulse-width modulation signals and I would like to do it from a single driver since they are uni-directiona... |
H: Possible calculation error using current divider rule on a non ideal current source circuit
I am going through my notes in preparation to an exam, the following was taken straight from the board as my lecturer wrote it.
As far as im aware the current divider rule should be $$I1 = It * (Rt/R1)$$
However it is writ... |
H: Any downside to using a charge pump for an op-amp negative supply
Background: I'm often building audio op-amp circuits for various purposes, and for small projects usually prefer single "wall adapter" supply. So for a ground reference I'll either use a simple resistor pair with a capacitor, or better, a spare OP am... |
H: question about transistor matching circuit
I'm studying this transistor matching circuit provided initially by Bob Moog. I think I mostly understand how it works, the op amp, bjt not under test and resistors form a current source, which stays constant for each transistor Vbe is measured for. What I'm a bit unclear ... |
H: Could a graphene battery / supercapacitor be used to power a railgun?
new to this StackExchange, but I have a question about graphene batteries / supercapacitor. From my understanding, graphene batteries / supercapacitors (not sure of the difference?) are superior to regular acid-based batteries because they can ho... |
H: Voltage drop of a non-ideal voltage source
I am having a problem with calculating the amount of current flowing through a branch, after deriving potential of its nodes using the Node Voltage Method.
I understand how to calculate voltage drop on a resistor and the voltage of an ideal voltage source as well:
The br... |
H: Disadvantages of Schmitt Trigger Inputs
I'm familiar with the utilization of Schmitt Triggers when interfacing with low slew rate signals / sinusoidal waveforms. In a recent design, I've been scrubbing our FPGA I/O configurations and noticed that I left the Schmitt Trigger on for a lot of I/O pins that don't necess... |
H: Help Interpreting "Max light exposure" rating for TSL1406R
I've purchased a TSL1406 Linear Sensor Array to read the position of a laser dot. The "Absolute Maximum Ratings" section in the datasheet specifies "Maximum light exposure at 638nm" as 5 mJ/cm^2. Being inexperienced with this sort of sensor, I would have ex... |
H: What are the options of having multiple I/O pins and a constant duty cycle?
For some context, I want to create something like this.
For now, until I change my chips (which I know I need to do as a plan to use a lower voltage Vcc2) I'm using the sn754410 h-bridge IC, 74HC595 Shift Register. I find that using two of ... |
H: What is "ripple bandwidth" in filter terminology?
I'm told "ripple bandwidth" is different from a "-3dB bandwidth" or corner frequency. How is this commonly defined, and how do I derive it?
My application:
There seems to be a discrepancy in the way Elsie (a filter design package, mine v2.75, fully registered vers... |
H: Control DC MOTOR from headphone
I would to know if is possible with simply way ( i'm not electronic expert ) to drive one direction a DC MOTOR ( a little ) from headphone, with power supply of course.
The difficulty is voltage of headphone, is very low 3mvw-6mw, is suppose is not enough to active logical input of L... |
H: Connecting different batteries in parallel - how to calculate the voltage?
I have an exercise: I have two ideal battieries connected parallel:
simulate this circuit – Schematic created using CircuitLab
I calculated a resistance of the whole circut: 0.666 ohm.
But how can I calculate a voltage of the whole circut?
... |
H: Effect of WiFi hotspot usage on mobile phone circuitry
Despite the fact that mobile phones come in wide a variaary and form different suppliers and with different software, most mobiles todays have a WiFi hotspot feature that can convert a mobiles' internet connection into a WiFi SSID.
Typically, mobiles phones hav... |
H: Does mutual inductance change individual inductances?
If I have two inductors, with inductances \$L_1\$ and \$L_2\$. I put them really close to each other to make a transformer.
Are their individual inductances still \$L_1\$ and \$L_2\$?
Or has the mutual inductance changed their individual inductance?
AI: It de... |
H: Questions about sound card scope software?
This is a popular software for those people who don't have a real oscilloscope or function generator:
https://www.zeitnitz.eu/scope_en
If anyone tried it before, would you answer my questions, please?
1.What is x-y graph? What does each axis represent?
How Can I measure t... |
H: Details on PCB layout for microcontroller
Update: the follow-up question shows my take on the resulting PCB layout.
I'm laying out my first board with a uC (I've got a reasonable amount of experience in using and programming embedded systems, but this is the first time I'm doing the PCB layout), an STM32F103, this ... |
H: Anti-aliasing filter as notch and lowpass
In order to reach a steep attenuation for an analog antialiasing filter, there are issues if a high Q notch filter is followed by a low order lowpass filter (or vice versa)? The notch resonance could make a brickwall filter near the cutoff frequency while the low pass would... |
H: Hooking up a variable frequency drive
I have a 3-phase blower motor that I am looking to control from a Danfoss VLT 2800 that I purchased on eBay.
I have in the shop a receptacle that looks like this:
If I put a meter from neutral (horizontal middle) to either hot side (the verticals) I get 120v. Across the hots... |
H: Minimum number of NAND gates required to realize EXOR function
While trying to minimize the number of NAND gates for realizing EXOR function,
\$A\overline{B} \ \cup \ \overline{A} B\$,
I used De Morgan's & got the expression
\$\overline{\overline{\left ( A\overline{B} \right )}\cdot \overline{\left ( \overline{A... |
H: What does this schematic symbol mean? (triangle with a line crossing it out)
I found the following circuit symbol in an MSP430 User's Guide in the section describing the ADC:
(I made a red circle around it)
What does it represent?
AI: The diagram on page 631 of the user guide has it labeled "Temp. Sensor".
This i... |
H: 2 Layer Through Hole PCB
I am designing my very first PCB for a robotics project I am working on. The project will be using through hole components. I was not able to get all the traces to work on 1 layer, so I added a second layer, the board layout is shown below:
Given this board layout, will I have any trouble... |
H: What tolerance do typical components have to wrong-polarity voltages/currents?
I've always been a bit hesitant to do continuity tests on populated PCBs, on the basis that if there is no trace connecting the two probes, I will be applying some finite voltage to arbitrary IC pins (quite possibly in the wrong polarity... |
H: Why the output voltage of dsPIC IO ports is not constant?
I expect output voltage of dsPIC pin should be 3.3V, and this seems to be true when the output pin is connected to high resistance.
However, when I connect to low resistance, the voltage of output pin is pulled low.(The image below shows the voltage is 2.75... |
H: Is BJT a Voltage controlled device or Current controlled device?
I have searched already for this question, but everywhere I see debate instead of clear answer. Though it is not that important of a matter whether we call it a voltage controlled device or current controlled device. I believe it can be called both vo... |
H: Computing Current from known Capacitance and Time to Charge to Known Voltage
If I know how long it takes to charge a capacitor of known size to a known voltage (within 10%), how do I find out the average current for that period of time? This only needs to be approximate.
Maybe I should ask this from another angle... |
H: How can I test the amount of power I can draw out of a USB charger?
I've got several USB chargers where the labeling has worn off. I'm interested in using some of these with a Raspberry Pi Model B, which needs at least 700 mA, as well as other devices with varying current requirements.
Is there any way for me to em... |
H: How does this blinking circuit with op-amp work?
Can somebody explain how this circuit works?
The OP tries to make the same voltage at the input cables.
At first, the LED is on. Therefore we have a low voltage (maybe 1V) on the negative input
The positive input also get this voltage (1V)
and then?
Why the LED tu... |
H: Circuits for two way data transfer from iPhone to Arduino via headphone jack
What I'm trying to do:
I recently bought an iPhone 3GS (yes iPhone...) and I am going to install Android on it so I can make apps myself for it and incorporate it in a bigger project, using the WiFi and the touchscreen capabilities to inte... |
H: DIY : Powering a single LED with a motherboard's internal connectors
I'd like to power a bright LED (1W or 3W) connecting it onto a power source of my computer, directly on the motherboard. I think about using either a fan connector or directly the ATX Power supply. But I don't find any information about how to do ... |
H: Multiple DC Input to Single DC Output
I want to connect solar panels in parallel, not sure whether connecting the terminals together will work. If one solar panel produces high voltage, it will block the voltage generated by second solar panel and it never contributes to the total power generation. This is my theor... |
H: 4-pin Hirose connector to BNC
Is there any way to convert n 4-pin Hirose connector to BNC ??
With this camera the the trigger is 4 pin hirose connector. But the trigger from my data generator DG2020A is 2state (0-5V) and a ( BNC output ).
AI: Yes, make a custom cable with a 4-pin Hirose at one end and a BNC at the... |
H: Measuring small Off state leakage current 10uA or less
I have a solid state relay an AQZ207 to be exact. I want to be able to measure the off state leakage current of the FET which in the datasheet seems to around 10uA Max. I had some ideas, but not sure what to do. I know the multimeter I have a fluke has a burden... |
H: Is there a way of conditionally triggering a compile-time error in verilog?
I have a parameterised module in verilog, where the parameters are a clock rate and refresh rate, which is used to calculate how many cycles of inactivity are inserted between instances of a repeating operation. However, it is very easy to... |
H: How do proceed with larger electronic projects?
Recently I have read two books about programming in general:
First one being Code Complete and the other being The Pragmatic Programmer that describe how one should think when dealing with large projects. Wonderful books.
My weak point is electronics. How shall one ... |
H: How Are Pixels Sent To The Screen?
So, today I started to wounder how pixels are stored, then push though the graphical bus. I have not really done much with LCD or touch screens. I do know from my programming background they are buffered, maybe in an array like binary structure. But I'm not sure. Does anyone have ... |
H: Can RFID readers submit scanned data to one location?
Let's assume that I have lots of RFID readers, is there a way, either a specific product or peripheral that allows the reader to send data about the tag it scanned over a distance of about 500m - 650m to one central location?
I have searched everywhere on the In... |
H: Turn S R Latch Using a NOR gates into NAND
I can't post a picture so the question will use Boolean Algebra. For me an SR Latch is
S NOR Q' = Q
R NOR Q = Q'
I will represent Q' as P since Q' might be mistaken as NOT(Q).
S NOR P = Q
R NOR Q = P
If I want to turn it into a circuit using only NAND gates it turns int... |
H: Powering two 8-Ohm speakers in parallel with a 4-Ohm per channel audio amplifier
Are there any possible problems powering two 8-Ohm speakers in parallel with an audio amplifier designed to drive 4-Ohm per channel? (Both the speakers and amplifier are generic, and the speakers are identical). The amplifier's power r... |
H: How to determine infrared protocol using PIC16?
I am trying to determine the IR protocol used in a Gree room air conditioner remote control. I connected the output of the original IR receiver to pin RA5 of a PIC16F73 and used the following code to measure the time periods of the high and low pulses.
while(1)
{
... |
H: How exactly do USB audio interfaces interface with a computer? (specifically ADC)
I have seen the likes of M-Audio fast track and similar devices that somehow covert an analogue voltage audio signal to a digital data stream which you can connect via USB to your computer. If I open something like Garageband it just ... |
H: Do I need to terminate extremely short traces (< 0.5 inches)?
Some background: I have a little hobby project running that basically interfaces a 64 pin ARM mcu (the STM32F405RGT6) to a stereo codec (a TI PCM3010) via I2S interface. I'm deriving the master clock for the I2S bus from the MCU (the stm32f4 series appar... |
H: How to identify orphaned power cords?
We are doing a massive purge of "stuff" from home and storage. I am accumulating a large quantity of random, unmarked power cords. Some will have "Nintendo" or "Norelco" on them - so I know to go confer with my boys about their gaming stuff or check my husbands grooming items, ... |
H: Magnetic Field Transmission
I have heard from here that if you put 1 turn of wire around your house, you can hear music all around inside your house. It doesen't tell me very much on all of the components etc. to drive but I am assuming that you have to have an amplifier on the receiver and the transmitter. To simu... |
H: How to program a BeagleBone board?
Until now I used Microchip PIC, to program this microprocessor there is MPLAB. I would like to make a step forward and learn about other microcontrollers.
I found the BeagleBone Black quiet promising for my DIY project because there is a 2GB flash and 1GHz clock.
I have a few ques... |
H: Running 7V motors with 2x 3.7v batteries
We're really enthusiastic to build a homemade quad-copter with almost no knowledge about such things. We will probably use Arduino and Bluetooth to control it, but we have a question about the motor power supply. We're planning to use a phone battery to power the motors. Our... |
H: DC 5V to 3.3V DC-DC Step-Down issue
TL;DR : The output voltage from my 5V DC to 3.3V DC stepdown seems to output 4.5V DC - why?
Background:
I'm trying to power an Airport Express from USB rather than a wall outlet. I have discovered that the PSU inside the APE outputs 3.3V DC which powers the device. I figured I co... |
H: why and how do I use a capacitor in a switch circuit？
I have seen many designs of switch circuit:
I know that a capacitor will help anti-shake but I realy do not know how i can anti-shake. Does it work like a decoupling capacitor or a low-pass RC filter?
and then I want design another switch circuit but do not kno... |
H: Run a processor through USB
I am really new to hardware design but have a fairly good knowledge of analog and digital circuits. I have only built one automated car using an Arduino board for a lab. However, I have really good knowledge of computer science.
I am trying to build a device with an operating system in i... |
H: To get rid of useless redundancy--do I realy need a voltage supervisor?
I am using a voltage supervisor from MAXIAM(MAX7634A). It monitors VCC_3V3 and VCC_-3V3(I use LM358 to make it a positive one).Power supply distribution is shown below:
VCC_3V3:
stm32f103
EMP570T144
some logic gates
some daughter board that us... |
H: 12F675: ICSP: /MCLR internally tied to Vdd
I'm using the 8-pin 12F675 so have to be conservative with pins. I want to use ICSP while having /MCLR internally tied to Vdd so freeing up GP3. The supply will be 5V.
I will be re-programming the chip via ICSP multiple times.
Reference documents: ICSP; 12F675.
Related qu... |
H: What modulation does Short wave broadcast stations use?
I have small Short wave receiver for the 7 broadcast bands. (49,41,31,22,19 and 16 meters) What Modulation do they use in this? The radio is a small grundig mini 300 world band reciever.
AI: All "short wave" public broadcast I have ever listened to were plain ... |
H: Driving LEDs directly from microcontroller pins
In the circuit I'm designing, I'm using an at91sam7s128 which is a micro-controller with an ARM7 core.
Its PIO0 to PIO31 provide 8mA max which is low to handle direct driving of LEDs like this:
simulate this circuit – Schematic created using CircuitLab
UPDATED: tha... |
H: Confusion between Voltage gain & Voltage gain in decibels (dB)
The definition of voltage gain is \$V_{\text{out}}/V_{\text{in}}\$.
However, I read some articles about the gain in decibels, and I have a confusion now.
Here is an article about it: https://en.wikipedia.org/wiki/Gain#Voltage_gain
Here, I understand the... |
H: Can I estimate remaining battery life by measuring its voltage with the same MCU that it powers?
I'd like to estimate the remaining battery life of a battery that powers a microcontroller. Could I accomplish this by simply leading the battery into the MCU's built-in ADC?
My idea is that I could plot the voltage ove... |
H: How to find τ in these circuits?
I know that \$τ = \frac{L}{R}\$, but what is \$R\$ in this formula? It seems to be the total resistance, but how to find it in the schematics?
AI: The arrows on the switches seem to indicate they are opening. I assume (but your problem statement should be more clear about this) ... |
H: Is there a minimum output current for voltage regulators?
I need both 4.5V and 3.3V for a project, and my idea was to power it using a single battery and a voltage regulator. A regulator I found (MCP1700) has an output current of 200 mA, but I'm only going to pull 3-4 mA. Is that large difference a problem in any w... |
H: What to look for in the datasheet when choosing a MOSFET?
I thought that choosing the right MOSFET for my LED strip would be easy until I discovered how many different models there are.
Basically I want a MOSFET that allows me to control with PWM a 12V 6A (MAX) led strip, but every time I see the Vgs I get confused... |
H: Binary to Gray Code
I have built this 3-bit Binary to Gray Code circuit. I would like to know if it is correct.
I have used 2 Xor gates.
AI: Your circuit is ok but you have inverted the bits order. If you try to make the truth table of your circuit you can see that sometimes changes more than one bit at a time and ... |
H: Sending ADC measurements with UART
I want to measure signal with ADC and send measurements to PC to generate plots.
My code:
ADC_SoftwareStartConv(ADC3);
while(1)
{
ADC3ConvertedVoltage = ADC3ConvertedValue * 3300/0xFFF;
ADCresultsTab[i] = ADC3ConvertedVoltage;
sprintf(str,"%u",ADC3ConvertedVoltage);
... |
H: How to cut interrupt code to minimum?
I have some interrupt let's say from UART to make a real example:
void USART2_IRQHandler(void)
{
int i = 0;
if(USART_GetITStatus(USART2, USART_IT_RXNE) != RESET)
{
static uint8_t cnt = 0;
char t = USART_ReceiveData(USART2);
if((t!='!')&&(cnt ... |
H: Connect micro gearmotor to 5V battery
Would 3 motors (like this one http://www.pololu.com/catalog/product/993) connected to a 5V battery (like this one http://www.dx.com/p/59438) work?
AI: The motors are rated for 6 V and that battery power supply for 5 V. The motors should definitely spin at 5 V unloaded, but wil... |
H: Single Bit Error Correction & Double Bit Error Detection
Can someone explain, in their own words, what Double Bit Error Detection is and how to derive it? An example of corrupted data and how to detect the double bit would be appreciated.
I can do Single Bit Error Correction using parity bits as well as correct th... |
H: Constructing an Encoder
I understand an Encoder is 2^n input lines and n output lines`.
I want to construct an Encoder from scratch so I can understand how it works, so that I can construct any other Encoder in the future.
I believe that the Input lines are an address to the output lines. So for a 4 by 2 encoder w... |
H: Voltage form at diode bridge
I want to find the output voltage of a circuit like this:
and this is my Matlab code to solve it:
function find_x
t = 0:0.001:10;
x0 = 0;
R1 = 90000;
R2 = 1000;
C = 0.001;
[t,x]=ode45(@rhs, t , x0);
plot(t,x);
function dxdt = rhs(t,x)
dxdt = -(C/R1 + C/R2)*x + C/R1*abs(si... |
H: Is my zener diode labeled wrong, or am i seeing a strange failure mode?
I'm experimenting with a power supply circuit to bring 24VAC down to 5VDC. I have an L7805CV, but rectified (a bridge) and smoothed (a 33μF electrolytic), the input is still \$40V_{peak}\$, which is more than the max input voltage the regulator... |
H: Thoughts on making a hand-held OCR
I have an electronic project about a OCR that could be held in hand and used like a Tipp-Ex mouse (image) to scan words. As I am an amateur in electronics, I don't really know what sensor(s) I can use to get a complete image of the word that I could process afterward. I thought of... |
H: Efficiency of a SMPS
I will like to understand the term efficiency in a SMPS design. Is there a way to determine the best efficiency for a particular design?
AI: What don't you understand?
Efficiency is simply a function of the ratio of power out to power in.
A Switch-mode power supply that draws 5W in and supplies... |
H: Help With Paper Calculation for Peak Rectifier Design Problem
I am tasked with designing a circuit for the following particulars:
A peak rectifier will be used as part of a DC power supply to supply an average DC output voltage of 15V, with maximum +/- 1V ripple. The load is 150 Ohms and the rectifier is fed from a... |
H: How DDR2 SDRAM works?
I have the Xilinx Spartan-3AN Starter Kit and I need to use the on board DDR2 SDRAM (MT47H32M16CC-XX). Until now I only used Static RAM and this type of memory is new for me. Can someone explain me how this memory works? What are the differences compared with a SRAM?
AI: Given the lack of deta... |
H: How can one mount PCB-mounted TO-247 devices to a large plate heatsink?
I want to mount multiple PCB-mounted TO-247 devices to a single large heatsink, something comparable to this:
My devices may or may not have mounting holes through them, and their tabs may or may not be isolated. Any approach will have to supp... |
H: LED remains off on ATmega16
I wrote this simple program:
#include <avr/io.h>
int main(void) {
DDRA = 0xff;
PORTA = 0xff;
while(1) {
}
}
When I program it to my brand new ATmega16A-PU, avrdude tells me that everything's fine. But when I connect an LED to port A, it never gets enabled.
For compiling the pro... |
H: Finding Impulse Response for System?
I have an LTI system with input and output related as per below:
$$
y(t) = \int_{-\infty}^t \! x(T-2)e^{-(t-T)} \, \mathrm{d}T
$$
and I need to find \$h(t)\$.
I am familiar with two methods of finding \$h(t)\$, namely, comparing the form to the traditional convolution integral a... |
H: How to power "arduino" from wall?
So I have a fake "arduino" that I put together (The main components on a breadboard, i.e. ATmega328, capacitors, ocilator, etc) and I am trying to use it to overide a light switch (When the light switch is off, power is off, when it is on, the microprocessor can shut it off manuall... |
H: How can output voltage and current of a DC-DC converter both be higher than input?
I'm working on a TFT LCD Supply and using a step up DC- DC converter from Maxim, the MAX17062. I want to find the input current. The datasheet lists that as 2.5mA. I have a doubt: if the input current is 2.5mA and the input voltage i... |
H: Isolated vs non-isolated triacs
Bt136-600 is an example of a non-isolated triac, while BTA08 is an example of an insulated triac.
What is the difference between an isolated and non-isolated triac? They seem to have the same symbol which is a bit confusing.
Could an isolated triac be substituted for a non-isolated t... |
H: Trying to understand how this op-amp sound module works
This is a schematic for the ZX sound module:
My understanding is that the first part is a high-pass filter followed by a non-inverting amplifier.
But isn't the second op-amp a comparator? It seems to me that it would output a HIGH if V- < 0.01*Vcc, or LOW ot... |
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