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H: Battery still drawing tiny current when fully charged
I have a device (a vaporizer) which contains a rechargeable battery. The battery only takes a couple of hours to recharge, but sometimes I end up leaving it charging overnight. I have monitored the current drawn by the device when charging, and to my mild annoya... |
H: Added parameter variant does not take effect
I want to add a parameter variant to my schematic. The parameter being varied, called "Load", does not exist in the DbLib from which I'm pulling my schematic symbols. Instead I've added the load parameter to certain symbols placed in my SchDoc.
I'm able to add a parame... |
H: How to pull Triac gate to ground with an NPN transistor with AC present
I am trying to figure out in this circuit, which lets the Triac 170 to conduct normally, which prevents an engine from firing, how to use an NPN transistor to replace the seat switch 154, but I assume there is AC voltage on the 112a line, and I... |
H: How to use 350mA constant current driver with a 180mA LED
As part of a domestic down-lighting system I've got a 350mA Constant Current driver, but i'm advised the LEDs I want to use should be driven with a 180mA CC driver. Changing the driver or LED's is going to be tricky.
Can anyone see any problem with putting ... |
H: Questions Regarding Symbols in a Schematic
So I'm building the circuit below as an exercise:
I have some questions on this schematic as I'm fairly new to reading schematics and electronics in general.
I have every component in the diagram but I'm confused on some of the symbols in diagram. What does Vin and Vs st... |
H: Why does this MOSFET switch on so slowly?
I am learning Tina and drew this simple MOSFET switch:
Adjusting P1 will at a certain point switch on the MOSFET, which I expected to saturate immediately. However when I look at the DC transfer characteristic, it turns on 'slowly' when the gate voltage moves between 3.5V... |
H: Magnetic induction on data lines from DC power lines
I have experienced failures of RS-485 links due to magnetic induction from ~52V battery power lines running very close in parallel. Standard shielding around the RS-485 cables did not solve the problem but a clearance distance of 1 inch did. The fault probably oc... |
H: MCU clock drift and radio frequency drift - are they the same?
Let's assume that I have two sensor nodes, one with crystal oscillator running at 24 MHz frequency, the other at 24 MHz + 10 ppm frequency.
To my understanding, in system-on-chip (for example, Texas instruments CC2650) based sensor nodes this single hig... |
H: Triac fan speed control
Are Triac based fan speed regulators harmfult to ceiling fans ? One shop guy told me that it's being replaced with capacitor based regulators now a days. But then how can the fan speed be controlled via microcontrollers without using triacs ?
AI: Are Triac based fan speed regulators harmfult... |
H: 12 potentiometers with multiplexer
I'm going to connect 12 potentiometers (100k) to a couple of cd4051 analogue (8->1) multiplexers and to 2 of Arduino (Uno) analogue pins.
Now I think each pot draws 0.5mA (I'm going to measure it to be sure) so around 6mA for all 12 pots. I think it is ok the Arduino permits 200mA... |
H: Datasheet register bit number
When it is written that to check if some flag bit is set, you have to look at for example 0x74[2], does that 2 means 3rd bit of register or 2nd? From which number they count in datasheet 0 or 1, how to determine that?
AI: It is common for register bit numbering to start at bit 0, but t... |
H: What happens to an electrical system at its pole?
Pole is defined as the value at which value of a function becomes infinity.
Let's say I have one LTI system with transfer function H(s)=1/s+1.
How the system will behave when s=-1.
From Bode plot I can see at pole the slope of Bode plot changes at pole frequency.
C... |
H: Why are 40 pin and above DIP packages generally wider than 28 pin and below
Take for example this datasheet for a Microchip PIC, the 40 pin package has a width of between 0.485 - 0.580 inches, while the 28 pin variant is between 0.24 - 0.295 inches. I have noticed this is the case with many parts, and don't remembe... |
H: Device/method for handling rapidly changing current demand in DC source
A circuit in my project uses rapidly switching MOSFETs to control current flow, and as a side effect, the current demand on the DC source varies rapidly.
The FET is switching at somewhere between 10kHz and 100kHz, and the current demand switch... |
H: Identification of component
I was desoldering components from a power supply board for a printer and I came across this small component. It was pressed against a heat sink so I assume it is some sort of thermistor but I am not sure.
The text on the component is "5104BL6"
AI: It's a temp sensor for laser printers.
B... |
H: Zener Diode + fuse overvoltage protection for LEDs with constant current driver- fast or slow blow fuse?
I am working with a 6-axis robot (UR5) with a smart camera mounted on the end of arm, and I want to add a ring light to the camera lens which I will power using tool outputs from the robot interface. The tool o... |
H: Footprint design for vibration resistance
I have a product that will be subjected to reliability testing (random vibration and thermal shock) and I need to design a footprint for an SMT power inductor that will give the best mechanical strength to resist damage during vibration testing. I've looked through the IPC ... |
H: PIC24FJ256DA210 issues with UART Receive, U1STAbits.URXDA never changes AND interrupt never triggers
I am having a problem receiving data. Using the logic analyzer I can confirm that Tx is working from the PIC. The Rx register (U1RXREG) is not collecting the Rx data and the data available bit (U1STAbits.URXDA) is n... |
H: What are these elements and what they do?
I have a telephone circuit (Model No. Panasonic KX-TS500MXB) which has following item between TIP and Ring. Do you have any idea what it might be? At first I thought it might be a back to back zener diode but after some testings I doubt if I am correct.
The following item... |
H: What is the purpose of diodes after RF power amplifier and before LPF?
I am planning to build an RF transmitter using an integrated PA module (RA30H1317M1). While studying schematics of similar transceivers, for example IC-2200H (that also has a PA module) I see all typical transmit chain components like the PA, fi... |
H: How do I reduce the rise and fall time to ideal case of 0 in my LTSpice model?
Working with basic circuit with pulsed voltage yields a rise and fall time or 0.5ns. My maximum time step is 1ps. With no delay , rise or fall times assigned. ( default assigned to zero) .
How do I reduce the rise and fall time to idea... |
H: How to find out a register contains inputs or outputs or both?
I don't have much experience with embedded systems and I am trying to check if is possible to determine if a register is made of inputs or outputs or a mix of inputs and outputs.
Let's say I have a 32 bit register like so: "11111111111000000000000000000... |
H: Is the voltage across a turned off transistor a problem?
I was studying some stuff here and I came across a question that I couldn't find on the internet. I created this circuit for demonstrating my problem:
The transistor Q6 is a normal NPN transistor, the only difference is that it's maximum Vce is 30V. Now here... |
H: Calculate gain of degenerated common-source stage using small-signal model
I have difficulties calculating the gain of a degenerated common-source stage, with the output resistance of the MOSFET taken into account. I came up with the SS-model below. I calculated the following:
The gain is defined as \$ A = \frac{v_... |
H: What do I have to learn to make digital wristwatch?
I want to make a digital wristwatch for my school project. So i want to know, what are the things that I have to learn in order to make digital watch by myself? As far as I know, I have to learn about microcontroller. But what else?
Thank you for answering
AI: Mic... |
H: Interfacing ILI9341 with PIC18Fxx series
I am new to embedded development, so please bear with me.
I have to interface a TFT display(ILI9341) with PIC18F452, it does not have any controller chip, I want to run a simulation with Proteus before getting the hands dirty with hardware. I am using mikroC PRO for coding P... |
H: How to use the Shutdown pin of a switching regulator?
What are the systematic/standard methods for incorporating the SHDN (shutdown) pin of a buck/boost IC?
Take MAX756 for example (datasheet).
Here are its I_q profile:
Suppose I'm using an Arduino nano (ATmega328) as the MCU and nRF24l01+ as the transmitter. I'm ... |
H: Question about 3/~5 output select pin of a boost IC?
I want to power up Arduino nano and nRF24l01+ 's Vcc from MAX756 step-up DC-DC convertor (datasheet). I'm using a single AA battery (1.5V)
There is a 3/5(bar) pin to select whether the output would be 3.3 or 5V.
The pin recognizes max 0.4V as low and min 1.6V as ... |
H: Mosfet as switch for high output current
I'm working on an android controlled input/output/gauges manager for cars based on a pic24 micro controller. I'm really not an electronics expert so I had someone working on the schematics but he has no time anymore. It's mostly done and functional but I'm having trouble wit... |
H: Hacking DSLR battery to power camera from power supply
I would like to power my DSLR for long captures with a power supply. I know the voltage and inner structure of the official batteries. The battery has 2x 3,7V cells inside with a circuit. People worked on this issue report that the battery's circuit is there to... |
H: How to determine a system is stable without knowing the input?
I was doing some exercises for an upcoming exam and ran into this. I am not sure how to find if the system is stable without knowing the actual input (since Routh array is the only method I'm familiar with.) (The answer provided is a)
Can someone explai... |
H: SST 39VF1602 - NOR or NAND?
I have this flash chip, and I cannot figure out if it is a NOR or a NAND flash chip.
Here is the
datasheet.
From the capacity of the chip (2M), I am assuming that it is a NOR chip, but I am not sure. How can you tell the type of this chip?
AI: It's implemented as a single array of para... |
H: What is sensor radius?
The manual for the bno 055 (link below) has an attribute for the sensor labelled radius on page 33.
The radius takes up 2 bytes of memory, the msb and lsb.
This already confuses me, as the msb and lsb are bits, but each register is for a whole byte.
Continuing, the radius of the sensor h... |
H: How to check if an IC is fried?
I was using my 74173 (d-type register) today and accidentally attached the vcc pin to ground and the ground pin to 5v. I didn't realize this and turned on the power. A couple seconds after turning it on smoke started to come out of the IC so I turned it off. I touched the IC a cou... |
H: If I have 5% 100k resistors but wanted 1% precision, can I use 4 of them in series parallel to improve on the 5% precision?
I made an error on ordering and am receiving a shipment of 5% 100K resistors when I wanted 1%.
This is for a voltage divider circuit.
Would it help improve the precision if I put two each in p... |
H: Damage a phone from intermittent charging?
Is it possible to damage a phone by charging it with an intermittent power source? For example, by using piezoelectric transducers in the soles of your shoes.
Assuming they're wired to a 5V regulator, will the constant oscillations between 0-5V damage the phone in any way... |
H: MCP6002 op amp without Vss Vdd connected?
I'm building a circuit from a schematic - K6BEZ Antenna analyser
Note there is no connection to pin 8 or 4 (Vss and Vdd) on the uppermost op-amp - as there is in the bottom one.
The circuit is not working - there is never any voltage at A0 - leading me to think there is so... |
H: Unexpectedly N-ch MOSFET high drain to source voltage in "on" state
Inside a bigger project, I'm trying to control a simple resistive load (A heating element) with an N-channel Power MOSFET. The load runs on two parallel lithium-ion cells, so at around 3.7v. The microcontroller (An Atmel Attiny85) which I am using ... |
H: How to design for a spectrum analyzer analysis?
I am designing a board that I will eventually have to hook up to a tracking spectrum analyzer to tune the PI circuit on.
I have 2 different circuits. The first goes RF-OUT -> PI circuit -> U.FL connector -> external antenna, and the second goes RF-OUT -> PI circuit -... |
H: VHDL process requires multiple clock cycles
I wrote a simple counter in VHDL for a program counter. Everything is done in a process, but what I dont understand is that in the simulation, the addition of the program counter, is only done at the next clock event, rather than immediately after PCNext has been output.
... |
H: what is the ideal number of contacts to be placed in NMOS and PMOS when drawing layout in Cadence virtuoso
I am trying to draw a layout for inverter and i am not sure about how many contacts to be placed in the diffussion region of NMOS and PMOS and what is the reason behind selecting that particular number of cont... |
H: vhdl port declaration with different sizes
I'm writing a vhdl model and I'm stuck with a problem about port declaration.
Let's say that I have an entity entityA that instantiates N entityB. Now, entityB has a port, out, with size M bits, and M can vary among all entities, so out is std_logic_vector(M-1 downto 0). T... |
H: How to simulate a mosfet from a datasheet in ngspice
First of all, I'm pretty new to the simulation side of engineering. I'm using gschem to draw simple circuits and I'm using ngspice from the commandline to run the simulation and plot the results.
So far I've succesfully done a simulation with a simple voltage sou... |
H: EEPROM Values Corruption - Only Some times
I am using 25LC640A EEPROM with a 32 bit Micro controller. This EEPROM can store 8kb of data, with SPI serial Communication.
In my case during every power down sequence MCU will write some block of data into EEPROM and then it will shut down. And also its working fine. I ... |
H: Implementing 3 variable boolean function od 2-1 multiplexers
Recently i've been given a task from my lecturer to implement \$f=\sum(1, 3, 4, 5, 7)\$ on "2-bit multiplexers". That's it. I assume he meant 2:1 MUX.
I've came up with following k-map...
+------+---+---+
| AB/C | 0 | 1 |
+------+---+---+
| 00 | 0 | 1 ... |
H: Arduino analog pin doesn't read correctly without connecting to gnd and Vcc of arduino
I'm using an LDR (photoresistor) with arduino and i have the following two cases:
Case 1:
I connect the input of LDR to Vcc of the arduino, The ground of the LDR to the ground of the arduino and the output of the LDR to A0 (analo... |
H: Remove switch off 'delay' from a Solid State Relay Board
I'm switching audio signals (line level) with a solid state relay board (Keyes - 8x Q3MB-202P), but when I switch off one channel, it takes some milliseconds (maybe around 500ms to 2 seconds) to really stop the signal flow. I believe this happens due to eithe... |
H: Analyzing a transistor relay driver
I found this circuit for a relay driver. It is similar to others I have seen, though it appears to have two extra parts that others do not have.
I mostly understand how it works, but I would like to understand it thoroughly, so I have some questions in my attempt to analyze it. ... |
H: How does an output switching from HI or LO to HI-Z affect an input in CMOS?
Let's say we have a tri-state buffer output connected to an inverter input, implemented in 7400 series CMOS chips.
If the buffer output is HI, the inverter output is LO. If the buffer output is LO, the inverter output is HI.
But what happen... |
H: How should I properlly draw on a schematic a shunt going through the center of a toroid coil?
So I'm trying to reverse engineer the schematic for an Avair AV-200CN SWR bridge. Two toroid coils, used for sensing, are mounted on a shunt, so that the shunt goes through the center of the coils.
I'm not 100% sure how t... |
H: Do i need to use capacitors with a 5v voltage regulator?
I am using a solar panel with a regular 12v charge controller but instead of using 12v batteries i am planning to use li-po batteries with a specific charger.
I know that the best way to step down the voltage would be a buck converter but i already have a L... |
H: Purpose of components in op-amp radio circuit
I am trying to understand the purpose of a couple of components in a schematic I am looking in at:
My questions are:
1) What exactly is the 100k resistor attached to the diode doing?
2) Why is the output of the rightmost op-amp fed into a transistor? Could the audio si... |
H: Determining necessary resistance in connections to IC pins
I'm building a portable 8x8 LED matrix with an attiny85 and two SN74HC164s shift registers, powered off of two CR2450 coin cell batteries and having trouble determining where to put resistors in my design.
To test the SN74HC164, I connected and powered it d... |
H: Designing a simple fan + resistor system for heating air
I have a research application that requires a steady supply of heated air. My current plan is to 3D-print a small tank (6" x 6" x 4") to which a muffin fan will be fastened. The fan will blow air across a 20W resistor into the tank to heat the air. The heated... |
H: Weird behaviour from a 40x4 LCD Character Display
We have a fire monitoring/management panel which has a 40x4 character display attached to provide information in the event of a fire.
It has recently started "glitching out", it displays random characters/glyphs for split-seconds in random places on the display. The... |
H: Heat dissipation in a DIP Solid State Relay
I am working on an application that switches a high power (15 W typical, 100 W maximum) resistive load at 230 VAC (RMS) from a 5 VDC control line. For this I plan to use a Solid State Relay. I am currently planning to use the AQH3213A from Panasonic, but I am concerned ab... |
H: Proper cut-off voltage for SLA battery in 120°F+ environment?
This is related to this question as well, in which I inquired about the most appropriate float voltage for a battery that would be in very high ambient temperatures, as the float voltage should compensate for temperature changes to avoid over-charging.
A... |
H: How much current the PS-on pin on the motherboard's power connector can sink?
How much current the PS-on pin on the motherboard's power connector can sink?
can it sink 100-200mA?
(to activate a relay/solid-state-relay when the motherboard wants to turn/keep on the computer)
(e.g. motherboard's PS-on pin >>> relay... |
H: Automatic switch on when sensor is activated
Im trying to find a component or to make a circuit to switch a dc wire when a sensor is activated and sends a voltage of 12V, like in the image bellow.
Thanks in advance.
AI: A relay provides a simple solution.
simulate this circuit – Schematic created using CircuitLab... |
H: HT7333-A LDO quiescent current
I've sourced some HT7333-A LDOs in SOT-89 package from random AliExpress seller for my battery-powered project. They were quite affordable and I saw some posts from people using these in batter-powered apps.
Datasheet on that IC states it has about 4 uA quiescent current and requires ... |
H: Will multiple chips outputing onto a bus for a few nanoseconds cause damage?
I'm working on a home-brew CPU design, with the usual mix of parallel EEPROMs, static RAMs and registers, tri-stated onto a single 8 bit bus.
My /output-enable logic for three tristate-able chips on the databus is:
/Ken = /a
/Ren = /a nor ... |
H: What if a capacitor exposed to slightly higher voltage than rated?
I'm building my 5 V circuitry for my bike's dynamo rated 3 W 6 V.
Today I went for testing peak voltages without load and capacitors, just with diode bridge 4 x 1N5819.
Unfortunately my multimeter doesn't have peak function, so I made peak detector ... |
H: Cross section of ceramic capacitors
I am trying to make a fault analysis of a bunch of ceramic capacitors.
Short description of the application:
10 220 µF ceramic capacitors 1210 package are placed in parallel with a 3.6 V battery. A MCU wakes up periodically (maximum once per minute) and draws current (maximum pe... |
H: Altium: Including Text of Evaluated Parameter in Value of Second Parameter
I would like to include the text value of one parameter in the value of a second parameter. In my case, I am trying to add on the text from the schematic SheetNumber parameter to the end of the text of the schematic DocumentNumber parameter.... |
H: Understanding work case of directional antenna
I try to understanding the workflow of directional antennas.
I want to implement a bluetooth communication with external, directional antenna. Lets suppose that I buy this:
https://cdn3.bigcommerce.com/s-blpsc02m/products/1667/images/1947/A2D5w__15836.1454272603.1280.1... |
H: Oversampling on dsPIC33EPXXGS50X family
I'm trying to implement oversampling on a dsPIC33EP64GS502. According to the datasheet and the 12-Bit High-Speed, Multiple SARs A/D Converter (ADC) reference manual I have to configure the following bits to set the oversampling ratio:
I'm struggling to understand why a 2x an... |
H: Does a fan need a flyback diode?
I'm aware that inductive loads like relays need a flyback diode. Since a motor is also an inductive load, I'm inclined to put a reverse-biased 1N400x diode across the terminals of this fan. However, I've never heard any mention of using flyback diodes with fans. Am I correct in t... |
H: Could sliding down a slide damage my camera?
Specifically one of those plastic spiral slides - I was at the playground with my children yesterday and when we went down the slide there was enough static generated to stick our hair on end. Of course my son has more hair than I do by now...
Anyway, there was a drasti... |
H: Optical perpendicular speed sensor required
I've been looking to this for a while now, and so far I can't find what I need. But I'm think I'm missing the right search terms for it..
I've got a little project in mind where I can measure the speed of a conveyor belt. I'd like to do this by having an arduino sized box... |
H: Beginner Q: Measuring current via USB charging cable
I was trying to use the multimeter to find out what current does my charging cable actually provides to the phone. How do I accomplish this without completely destroying my cable?
Right now I can measure the voltage (~ 5.15 to 5.2 V) and V~ (Ac voltage? which is ... |
H: How to reduce/remove piezo pickup hiss
I made a stompbox which is basically a small wooden box with a piezo element inside that when stomped on produces a sound similar to a bass drum except that the thing is much more portable.
The circuit works but I have two problems with it that I don't know how to solve:
It'... |
H: Matching sensor output with PLC input
I am trying to add a height captor for a line of my production where I work. I found this Banner captor (QS30LLPQ) and it has 2 bipolar discrete outputs (PNP and NPN). Now, I am trying to decide which of those two outputs I should connect to the input card of my PLC. This input... |
H: What is the IRQ out in I2C?
On this MPR121 capacitive keypad (link), what is the purpose of the IRQ out?
AI: What is the IRQ out in I2C?
I'll give a slightly different focus from some other answers.
Remember that I2C Slaves cannot initiate an I2C bus transaction. Therefore if you have an I2C keypad or touch screen... |
H: Does cassette tape change its velocity while playing?
Looking at the old cassette tape,
From the POV of the head, let's say that it reads at speed \$v\$ (the magnetic medium scrolls at speed \$v\$).
But looking at the right wheel, which is the one that's pooling the magnetic medium - its radius is growing(!) over ... |
H: Should I use cascaded regulators, or connect them all to the same input?
For a particular design, I need to take an unregulated voltage from a battery and regulate 5 different DC voltages from it. What's worse is that I need step-up and step-down converters. What's even worse is that some voltages need more current... |
H: First Arduino Board Design
This is my first designing an Arduino 'shield', so I wanted to get some input. This board interfaces with sensors using I2C. A Raspberry Pi interfaces with the Arduino, which reads magnetometer data from six to seven different sensors through an I2C expander. The schematic can be shown be... |
H: Wiring a switching regulator, two relays, and a LED…
Currently I’m working on a small portable amp which will be run either with 17 to 24 volts, depending if I drive it with a battery or a wall wart. It’s my first electronics project, so I have some fairly basic questions...
To power two single coil non latching re... |
H: Clean water turbidity sensor
I'm working on a project to determine the water clarity, using a MCU with a turbidity sensor. I have tested sensors such as: Cheap Dishwasher sensor, and while it works for changes in turbidity in dirty water, it isn't great with clean water.
For example, the water I am testing in the o... |
H: How to step down from 4.5V to 3.3V?
I'm trying to step down my source voltage of 4.5V to a 3.3V suitable for the MPR121. The chip has at the best settings a typical current of 393μA. The 3.3V has to be quite accurate as to not damage the keypad. When researching, I've come across two possible solutions that could a... |
H: What kind of LC circuit can produce this response?
I am trying to come up with an equivalent circuit for a structure that I'm working on. The response is shown below:
The modelling of the structure hasn't incorporated any loss, therefore the real part of the impedance is 0. I am not a circuit expert, and would lik... |
H: How to use a reference design in datasheet?
I'm trying to gain a better understanding on what this is and how to use it. I know this is a datasheet for SAMB11 SoC, more specifically the reference design on page 50 is what I'm inquiring about.
In a general sense, is a reference design the simplest/fastest way to g... |
H: How to direct input and output of circuit for multifunctional 4 bit calculator
I am trying to build a 4 bit calculator that can add subtract and multiply using a FPGA board (Altera DE2). I have an adder/subtractor and multiplier already built and functioning but need to know how I can merge each function and give ... |
H: Bright flash using capacitor and LED?
I'm looking to produce an intensely bright single flash exceeding 2000 lumens for half a second. If I hook a charged 10,000uF electrolytic capacitor up to a 100w LED chip, will it work and how bright will it be? Is there a better way of doing this electronically?
AI: If you wan... |
H: AM (Amplitude Modulation) Colpitts
How would I amplitude modulate the Colpitts oscillator directly?
Can this be done by making Vcc the audio signal and DC offsetting the audio signal in order to get the Colpitts to fundamentally oscillate?
AI: You can't push a colpitts oscillator (or hartley or clapp) too far bec... |
H: Why does this isolation transformer have another transformer in it?
The isolation transformer I'm looking at: http://www.mouser.com/ds/2/336/HX1188NL-515471.pdf
My question is why is it there? Is it not enough to have just the transformer on the left?
AI: That "transformer" is a common mode choke.
It's used to sup... |
H: N-MOSFET and high frequencies
I am using this Mosfet (http://www.vishay.com/docs/91017/91017.pdf) as a switch.
Vd is a sinusoid, amplitude = 2V
Vgs is either 0V or 5V.
In low frequencies (less than 1 MHz), everything is fine:
-if Vgs is 0V, Vs is 0V
-if Vgs is 5V, Vd is a sinusoid.
However, when I use frequencie... |
H: What does the reference designator NT mean?
I found NT1 in a Microchip demo board schematic (103-00419-R1.pdf) but can't figure out what it means.
There is a box with a note saying "Default connection between 1-2. User to cut the trace if 5V VDD is needed.", with NT1 as a little box with wires going to pins 1 and 2... |
H: Protecting circuit from railway's high voltage
I am designing a control system which is going to be installed near a functioning railway. The system has many interfaces that are externally connected to different devices, it has Wiegand, RS485, Ethernet and a few digital IO pins.
I am currently thinking of using va... |
H: Quality parameters to include in contract with hardware supplier
my company (not related to electronics at all) is now getting a simple control board for a product designed by a third party. The very same third party will also be in charge of building such control boards, realistically for the lifetime of the produ... |
H: Upper limit for resistance values in voltage divider?
I am measuring the voltage of a 24 V battery using the ADC from Arduino Uno. I use a voltage divider to bring the voltage below 5V (the maximum the ADC can accept).
I noticed that as long as the ratio of R1 and R2 is the same for my voltage divider - it's better... |
H: Opamp Unity gain follower stability
Please give explanation considering opamp as ideal one as well as practical one.
Edit:
I got the explanation here. Decompensated Operational Amplifiers
AI: Ideal op amp: stable with infinite bandwidth.
Practical: look for opamps that are guaranteed "unity gain stable" (most mo... |
H: How to find input impedance of RA30H1317M1 RF power amplifier module?
I am building an amateur radio VHF transmitter. I want to use off the shelf transmitter module like DRA818V (or similar) as the drive amplifier and RA30H1317M1 as the final amplifier.
This is my idea:
simulate this circuit – Schematic created u... |
H: How to make a variable frequency circuit
Anybody can explain how do I make my circuit for variable frequency output with variable resistor not trimmer/variable capacitor my circuit shown in fig
AI: If you replace C4 with back to back varicap diodes you will get some control of the filter frequency. A BB171 has abou... |
H: Load-line of MOSFET when analyzing triode mode
When we are analyzing MOSFET within a circuit (e.g. as an amplifier) with drain or source resistor we must consider the load line of transistor, like so:
When used in triode mode a.k.a. ohmic mode there is said that drain current increases linearly with drain-source v... |
H: Why does four Apple Model Numbers (A1457, A1518, A1528 & A1530) have two FCC IDs (BCG‑E2643A & BCG‑E2643B)
These are model Numbers of iPhone 5S.
I want to know why two Model numbers of iPhones have the same FCC ID?
I am assuming that as they are two models, they are NOT the same for Apple yet they have the same FCC... |
H: Convert 24 V to 20 mA (none is variable)
I have a PLC (take the "P" with a pinch of salt), it has some analogue inputs (4-20 mA) that I need to use to detect if 24 V is present or not.
I can program the logic to say above X mA 24 V must be present, below X mA it mustn't be present (the reason is I have some contro... |
H: How to connect a diy audio signal to my "expensive" audio interface
I'm a hobbyist and after some experimentation (around 4 years) I want to connect my signals I create on the breadboard to my expensive audio interface. Until now I was using the "mic" input on my laptop to connect the signals and I haven't damaged ... |
H: Working out AT28C16 LED output from datasheet
I'm trying to work out how to connect some LEDs so I can view the value of the value stored in the AT28C16 (pdf) chip.
I'm actually following a youtube series. In the video he chose a 330Ω resistor but I'm not sure how he would work this out given we don't know the maxi... |
H: Driving a laser diode with an LM317
I want to make a a line of sight sensor. I want to drive a laser diode with constant current and aim it at a photodiode, then using a transimpedence amplifier I will monitor any changes in light intensity. The reason I am using a photodiode and a laser diode is because I want fas... |
H: 20 Mhz AM transmitter and receiver - Receiver does not receive
I am doing a circuit for an AM transmitter and receiver. I extracted it from http://www.pyroelectro.com/projects/pyro_rf_receiver_27mhz/index.html.
Receiver:
I have already done the transmitter, and the antenna seems to irradiate as there is some inte... |
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