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H: Buck Converter Control Scheme- Why isn't just a comparator not enough?
I am supposed to come up with some control schemes for the converter before understanding the standard PWM control scheme.
Isn't it just enough if the output of the converter is compared with a fixed reference voltage to drive the output to req... |
H: Is the given voltage Peak Voltage or RMS Voltage
In circuit diagram problems is the labelled voltage RMS voltage
or Peak Voltage ?
For example say in problems like this what is the usual convention?
I recently started learning about circuits and i'm in high school.I don't know if the question is suited for thi... |
H: MOSFET fast turn-off not enough
I have a PWM bridge driving a higher than 1k load from 200V supply. The simplified, equivalent schematic is this:
The drivers I'm using are slow turn-on/fast turn-off and, in the schematic, it's a 50% duty-rati.,The parasitics modeled here also involve some capacitance across the fil... |
H: Step motor intermediate position
Is it possible to change the position of arrow to be a little more to upper winding or right winding? If we supply different values of voltage to two winding what will happen to arrow?
AI: Yes.
It will tend to move to an angle of arctan(V1/V2). |
H: Amplifier impedance matching with constant voltage speaker systems
I understand that in order not to potentially overload an amplifier one should connect a speaker with an impedance no less than that specified, and I have just recently come to understand that for maximum power transfer the amplifier and speaker imp... |
H: Extending diode with a buzzer
Basic idea is to extend existing device with a buzzer: I want to make noise when one of the diodes lights up (DL12 on the attached picture). From the layout of the board I assume that U1 (M74HC595) is driving both rows of LEDs (DL8-12 and DL13-17, only one diode from each row is lit at... |
H: How do TTL NAND gates work?
This is supposed to be a simple NAND gate.
I understand how the output is 1 if one of the inputs is zero
but if both inputs are 1 then the base of Q1 is supposed to be zero. This is what I don't understand. I know that Q2 and Q3 will be in cut off so the base of Q1 is floating. If that ... |
H: What are limitations of Kirchhoff laws in presence of A..C current.what are the bounds on its application in such case?
I'm not able to understand while Kirchhoff's laws seem to be based on very fundamental logic they are still not applicable in some cases.
I tried to look for answer in text book but got no clear v... |
H: How to calculate base-emitter current
I want to use a BC547 transistor to switch a MOSFET. The base-emitter side should be driven by a Raspberry Pi. The maximum output from the Pi is 3.3V, maximum current is 15mA but I would not like to have more than 6-8mA for safety reasons - output pins are connected directly to... |
H: Calculating Power and Setup using resistors as heating elements
I looked around at other questions, and either I didn't understand what all I was reading, or it didn't answer my question so if there is an article that I've missed feel free to redirect me.
I'm fairly new to electronics, and came in through Arduino s... |
H: Why do I get a "[Synth 8-5413] Mix of synchronous and asynchronous control for register" warning in Vivado?
The code bellow is to take the reciprocal of a fixed point number using Newton's method. When start is asserted the state machine enters the estimate state. To get a starting point, I start at 1/2^N where N ... |
H: How does a momentary dpdt switch function?
Ok I'm feeling dumb right now. I got one of these momentary dpdt switches and can see via ohm meter that the middle terminals are normally connected to one of their corresponding edge terminals when the switch is "NOT pushed." However, when I push the switch, I see the con... |
H: Is it a good habit to route wire under chip resistor/capacitor?
Is it good/safe to route under resistor/capacitor? As below, it's a 0.5mm wire under a 1206 chip resistor.
AI: It depends.
If you have a high density board, you might have too, otherwise it means you need a via, or have to take some irregular path on ... |
H: Calculated MOSFET switching time does not agree w/ expected results
In preparation to design my own boost converter, I am trying to analyze the poorly-performing 555 boost converter circuit discussed here (so that I know which mistakes to avoid):
555 timer boost converter doesn't meet spec
The circuit is reproduced... |
H: Why does capacitive loading occur when using passive oscilloscope probes?
I was recently reading an article written about oscilloscope probing. And at one paragraph there is a comparison between active and passive probes as in the below quote:
"For high-frequency applications (greater than 600 MHz) that demand prec... |
H: How actually an integral transformation(Fourier and Laplace) works?
After seeing a question on one of the posts I got this confusion in my mind. Here I'm not much interested in just mathematical explanation but I would like
to know how a transformation actually turns a time domain signal to frequency domain. And wh... |
H: Can an opamp be neither in linear region nor saturated?
I'm trying to build a voltage controlled DC current source. For this, I built this circuit:
A little bit of context. The voltage supply is 5V. Current range must be from 0mA to 30mA or so. Load will be an LED but for now I'm just connecting the collector to ... |
H: LED light bulbs flicker when switched off - where does the energy come from?
Outside my house, at the front, I have a set-up of 3 lights attached to the wall. These lights can be switched on using a switch inside the house. Furtermore, they are attached to an infra-red sensor which can switch the lights on for 2 mi... |
H: Multi channel variable speaker design problem
As part of my my consideration of possible solutions to my multi channel variable speaker number problem arising from my attempts to restore radio functionality to an old hotel intercom system (see previous post on the subject if interested) I have been considering how ... |
H: Connecting a Raspberry Pi to a 220V switch
I have a switch that works at 220-230V AC and I'd like to link it to my Raspberry Pi and I want to know what I have to do from an electrical point of view.
So my switch, when switched on, places 220V AC on a wire, which somehow I'd like to transform it to 3.3V DC so I can ... |
H: Reset Power using 555 timer
I'm trying to cut the power for 5 seconds to my circuit every 30 minutes using a 555 timer. I've been trying to design my circuit using 555timer and NPN but im not having any luck with it has anyone got any suggestions?
Input Voltage: 5v
AI: The evil 666 555 timer is inappropriate for du... |
H: Arduino's Resolution with Multiple Analog Inputs
Resolution of an analog to digital conversion means the ratio between the maximum value of the measured signal to the number of data point that it can resolve(0-1023). So for Arduino(10-bit) my resolution is 5V/1024=4.88mV. Now I wonder if this value changes when I r... |
H: generate high voltage using LM555 with a transformer
I'm a French student (please forgive my bad English spelling) who works on a system of portable echograph (you can find the information of the project on the wiki of echopen). Could you help me please?
I would like to generate a tension of 100V. First, I took a t... |
H: VHDL simulation shows 'X' for input
I'm new to VHDL and I'm trying to simulate an array multiplier.(I have used verilog before). However in the simulation results it shows 'X' for inputs which used to be '1'.Here is the result:
And this is the Testbench:
LIBRARY IEEE;
USE IEEE.std_logic_1164.ALL;
ENTITY array_mult... |
H: Jumper Setting Modes in PIR motion sensor
I was going through the data sheet of the PIR motion sensor when i saw this:
So what i couldn't understand was the H and L trigger and how to change from H to L or L to H (like to do we have to provide HIGH to the H trigger to activate it or something else). I found a littl... |
H: What does this schematic symbol mean (similar to solder bridge)?
this symbol is similar to solder bridge, but there is a connection on both end.
what does this symbol mean, and what is the equivalent pcb for this symbol
AI: It really is a solder bridge, with a separate trace connection as well. The trace can be cut... |
H: Barkhausen condition on a Wien oscillator
Consider the Wien oscillator:
We can determinate the operational amplifier gain defined as:
$$A(s)=\frac{\bar{V_o}}{\bar{V_a}}$$
and the gain from the feedback network:
$$\beta(s)=\frac{\bar{V_a}}{\bar{V_o}}$$
where \$\bar{V_a}\$ and \$\bar{V_o}\$ are the complex amplitude... |
H: How to fade in and out light bulb(220V) (Arduino)
I have relay conected with arduino and high voltage bulb, now how can I control voltage to fade in and out bulb? I know that a relay is an on off device so maybe a triac or IGBT would be needed?Would an optpcoupler be good for isolation? Should I use a PWM output on... |
H: Arduino - Detect tone
I've got a strange setup:
Background:
I'm building a wireless binary transmitter with a couple of low powered CB radios. I've re-soldered the activator button and microphone on one; that sends two different tones (1500hz for 1, 1000hz for 0); this end of the setup runs beautifully with my Ardu... |
H: Safety when using ATX power supply as benchtop supply
I found many pages where people convert an ATX power supply to a benchtop power supply to give 12, 5, 3.3V.
However the current output can be very high (several amps).
When using this and you NEED high current, that is great. However, when using this for typica... |
H: How to automatically switch RF path to external antenna
I'm designing a circuit that has 2 antenna options for one transceiver @ 1.6 GHz. One antenna is internal and is the default RF load. Another antenna is external - to be attached by the user if desired. If and when the external antenna is attached, an RF sw... |
H: Schematic to wiring diagram check for 3 mic mixer circuit using TL081
Need a bit of community validation to see that mapping of the following circuit schematic:
to this hand-drawn wiring diagram seems correct, and there are no obvious mistakes:
Also, does having 2 (or 3 inputs) instead of the 4 shown in schematic... |
H: Overcharge Lithium-Ion when using charge controller + Arduino Load
I'm trying to determine if I need to rethink my circuit for a solar + Li-Ion powered Arduino. Basically a solar powered module with 3.7V Li-Ion backup for night / clouds (to be charged during the day). Being my first go at utilizing solar + recharge... |
H: LM358 as a comparator output problem
I've got an LM358 based ground fault detector circuit that I've recently revised, and the revision broke it, so far as I can tell.
To make a long story short(er), what it amounts to is using one of the LM358 stages as a comparator has whacky output levels. There's a 5 volt suppl... |
H: Why does this circuit work?
I'm suffering from a bit of confusion here and I was hoping that some kind soul here would be able to help me out. I want to build a small DC motor circuit just for fun, but I can't understand some aspects of the circuit (shown in the picture below)
.
So basically I understand that Ic =... |
H: Which is correct, kohm or kOhm?
Should the unit "Ohm" be capitalized or not? For example, "kOhm" versus "kohm" vs "kΩ", which is most correct?
AI: In my experience "kΩ" is preferred, but if you don't have the "Ω" symbol available on your computer then you need to write out the full words in lowercase: "kilo ohm".
... |
H: Volume of sand in a cat box - ultrasonic sensor?
My cat is always making fun of the sand that is inside of his sanitation zone :)
In order to better control the amount of sand that is present on the container I'm developing a communications circuit to collect data from the box. But I would like to develop something... |
H: Glass fuse identification - Siran No. F 13 4A
We have a glass fuse for a 12v lighting circuit that has
"Siran No. F 13 4A" written on paper inside it. The circuit takes 5.5A at the moment with all the lights switched on without the fuse blowing. Can someone tell me what this is rated at? It seems to be a fast blow... |
H: Is a Van de Graaff generator a voltage or current source?
I'm currently studying basics of electrostatics and this question comes to me as any generator must be from either of the two types but which is the fact I'm not able to justify which. From its internal construction it does not simply fit in either of the tw... |
H: Startled by a notation of operator for combining two signals
I am studying electronics and when practising, I got stuck at this simple problem of summing two signals. I believe I know how to work out everything except the combination of the two signals with two "minus signs".
The problem is
i.e. one signal of 0.1... |
H: Mosfet is getting hot under 3v drive
I have a Arduino controlled RGB strip, which uses PWM to control the brightness of each colour. I have been using an Arduino UNO to do this but I have have just upgraded to a Photon by particle. Similar to a micro Arduino but with wifi shield built in. The main difference is tha... |
H: Charging all night and its effect on the charger
I googled about this topic and I found that keeping the charger plugged in the wall for days will consume a very small amount of energy and will not cost too much. And most of smart phones disconnect the battery from the charger automatically when the battery is full... |
H: Advice needed: comparing two parts
I want to buy some 0402 SMD capacitors (well some is about 1 to 10k).
I always use the method of use the cheapest part for the given specs approach. But today I noticed something odd:
I was comparing these two parts on digikey:
Partno. Price/piece Price for 10k
---------... |
H: Ways to voltage shift a wave down to ground
Say I have a wave signal that is always above ground, that is, the signal is positively clamped to the ground.
(EDIT: from an input of a helpful user, I now know this should be called "negatively clamped", my mistake)
simulate this circuit – Schematic created using Circu... |
H: What is the difference between worst hold slack and worst negative slack
I have been looking all over google and I can't find a clear answer for what is the difference between worst hold slack and worst negative slack in the timing summary in vivado. Right now I am building a integer divider and I am passing the w... |
H: How to pick MOSFETs and drivers for FPGA BLDC driver?
I am building a Brushless DC Motor driver based on an FPGA.
I need to pick the transistors and drivers.
Do I need an IC driver or can I use smaller transistors?
The motor runs on 15A/16V.
I am estimating 50kHz switching frequency.
To be able to use them without ... |
H: High Current DC Power Supply
I'm attempting to build a compact way to charge six laptops (of the same model) so that I may avoid using six individual power cables. I'm trying to make it cost-effective yet safe.
My initial design was to take a simple 24V 15A DC power supply off Amazon and branch the output connectio... |
H: Does PCIe hotplug actually work in practice?
I've got into a discussion in the comments of https://security.stackexchange.com/questions/109199/is-physical-security-less-important-now-for-securing-a-server?noredirect=1#comment194327_109199
The question is simple. Has anyone experience of successfully hotplugging a ... |
H: Is there any material that obstructs or resists capacitive sensing?
For example, is there any material I can place over a capacitive sensor, or the finger or conductor approaching it, so that the sensor will no longer activate?
AI: A capacitive touch sensor sort of forms a parallel plate capacitor with your appenda... |
H: Question about FTDI USB-to-Serial Evaluation board
The evaluation board
I am talking about the FTDI EVAL232R evaluation board which can be found at the bottom of this page. It employs a FT232RL IC.
What I want to do
I would like to connect a USB joystick to the board´s USB port, then connect the RS232 interface to ... |
H: Does a boost converter lower the source current of a solar panel?
I am trying to build a solar powered phone charger using small size solar panels. I have two solar panel connected in series, each of them are 4 V and 50 mAmps. When I connect the solar panels to the input of the following boost converter, it shows i... |
H: Help understanding transformer AUX winding
I'm new here and I'm looking for someone to help clarify the AUX winding of a transformer, more specifically in a switched psu.
I see schematics where it's being used either as feedback or voltage input to an ic on the primary taken from a winding on the primary (at least... |
H: 4s2p lithium ion battery charging from USB
I am newby in electronics. I planning to design a 4s2p (3.7 V, 3000mAh) li-ion battery pack and a charger. I want to use TI BQ series (BQ24618) ICs for charging. I know we can charge battery pack with 14.8V+ DC.
Can we charge the battery pack also from a USB (5V) input. I... |
H: In a circuit with the TI TPS61165, how was D2 chosen?
Looking at datasheet for the TPS61165, I don't see how they chose D2 - it looks like it will only work if the voltage supply is above 12v due to this diode, but the chip's input range is 3-18v. I would like to know if I can replace it with say a 9v diode, could ... |
H: Noob Measurement Mystery
I am taking up electronics and bought some used test equipment. I have been measuring anything and everything, sometimes with unexpected results. Above is one of those cases.
The function generator is outputting a sine wave of 1kHz at 5Vpp. It shows up as expected on the oscilloscope. The ... |
H: Calculating the time for current reducing to zero from a charged inductor in a series LC circuit
I'm wondering how you calculate the time taken for the current in a charged inductor to reduce to zero with the only current path being through a capacitor. I'm looking at this from the perspective of an unloaded boost ... |
H: Backup power supply with led
My project requires a backup power supply, and I want to include an LED to determine when the backup power supply becomes active. My thought was a voltage divider to limit current to the LED, and allow the excess to bypass the LED and go straight through to the load.Would connecting a B... |
H: Why more, smaller transistors increase power efficiency?
Transistors, bjt, MOSFETs OK got it.
More transistors = better computing got it.
But compressing the transistors closer to each in my mind only helps reduce the physical dimensions.
So does a CPU or any electronic become more efficient because the transistors... |
H: How do I lay out PCB traces for a given "differential impedance"
This is an attempt to craft a good general question and answer for a topic that's been asked before, but only in specific situations.
Could you describe what I need to know, prior to laying out a PCB board for a differential signal pair with a specif... |
H: Switching 15V, 1.5A AC with SSR
I need to switch 15V, 1.5A AC into a resistive load with a 5V control signal. Will this SSR work?
http://cpc.farnell.com/crydom/aso242/ssr-2a/dp/SW03811
To be specific, I do not understand the term 'minimum operating voltage: 24Vrms'.
AI: If your operating voltage is 15Vrms then it w... |
H: Meaning of strong and weak drive in VHDL?
What is the meaning and effect of "strong" and "weak" drive shown by (0,1) and (L,H) in VHDL's package ieee.std_logic_1164?
AI: The ieee.std_logic_1164 package allows two drive strengths.
(0,1) are normal drive strength and used for all normal purposes.
(L,H) are weak driv... |
H: Why does this bridge rectifier claim to have no diode forward voltage drop?
I was, "OK, this is feasible," but then I traced how it worked and it simply blocked current through drain and source when a P and N pair are reverse biased. When the other P and N pair are forward biased current flows through forward fio... |
H: Transfer function in a 2L2C circuit
I have to find the transfer function of the following circuit (AC, sinusoidal), using complex numbers, Kirchoff point rule with potentials or Millman's theorem.
The transfer function is \$\underline{H}=\frac{\underline{i_1}}{\underline{u}}\$ .
Here is what I did for now. Schemat... |
H: Set multiplexer inputs to a logic 1 state
How can I set, in Orcad, all the entries of multiplexer(in the picture) (except: 1, 13), to logic state '1' (for example, I understand that if I place 'ground' to some entry, then it will be equivalent to '0' logic state. That's what I want to do for '1' logic state) ?
AI: ... |
H: Connecting active filters in parallel
I would like to connect a signal coming from a line receiver to several op-amp based filters in parallel. The basic topology (high-shelf) looks like this:
simulate this circuit – Schematic created using CircuitLab
What I don't understand is the meaning of R1. Why does the posi... |
H: How to "spread linearly" the force of a solenoid
For a pet project of mine, I'm interested in finding a tubular solenoid which force is spread linearly over a longer length. The project is based on IA and uses a programmed controller (and sensors) to feed several solenoids (the question is for one solenoid) quickly... |
H: Summing amplifier with bypass
I am trying to sum three audio signals using a non-inverting summing amplifier as shown below. If I want to bypass one of those signals, what is the correct way of doing that (let's say with a switch)? Connecting the route to ground as shown?
I assume just disconnecting the signal fro... |
H: Influential factors setting the operation point of a bipolar transistor?
I do know why and where we should set the operation point of a transistor. We also learned calculations during lecture. However I do not know, what values do we change to set the Ib DC current. Are we changing the resistances in the system, or... |
H: OrCad issue: Logic circuit simulation....ambiguous output
After simulating the following logic circuit(in OrCad),the resulting output -'y' is unclear. It seems to me that everything is fine, yet the result is ambiguous.
Can you, please, explain what is the problem here ? Thank you in advance.
The Circuit:
The ... |
H: Keeping inputs to opamps
I'm trying to get the hang of op-amps, and I've run into a stop. I'm trying to implement a differential op-amp, where the two inputs are from a wheatstone bridge. Please see attached diagram
The problem I'm facing, is that the inputs \$V_{left}\$ and \$V_{right}\$ change, due to the impedan... |
H: How to replace a switch with a NJK-5002c hall sensor?
I'm building a 3D printer, and I want to replace my endstop switches with hall sensors instead. I've bought some NJK-5002c hall sensors from Ebay, but am unsure how I can hook them up to replace the switch.
The previous setup that I have, which works, is that e... |
H: Help me to identify this pin
I found this type of pin in some 3 pin female connector. I want to buy it but I don't know what is name of this pin :)
Any idea?
(I put dimensions approximatively)
Here are dimensions of plastic connector:
AI: It's most likely part of Molex's KK Series.
There are many alternatives made... |
H: Blocking DC without blocking any frequencies?
Is there any practical way of blocking DC without blocking any AC frequencies (or as few as possible)? Suppose I wanted to block DC and let through all frequencies between 2Hz and 10Ghz with minimum resistance.
The first methods that spring to mind would be to either us... |
H: Transistor Based Wien Bridge Oscillator
I've been studying the schematic for this RLC Bridge from Heathkit (IB-5281). The full pdf can be found here (search for the part number): http://www.vintage-radio.info/heathkit.
The circuit contains an AC source to drive the bridge which is basically a JFET Wien Bridge osci... |
H: How do I calculate the voltage in this circuit?
I have the following circuit:
I am a beginner at this stuff, so... ;)
Ok, the question is to calculate the voltage across the terminals A and B? I have no clue how to do that? You can't just take together some of the resistors. The Node method seems a little overkill... |
H: Noise in simple BC547-Raspberry Pi GPIO doorbell?
I've connected a Raspberry Pi to my Friedland "Ding Dong" doorbell. The doorbell has two (apparently unused) terminals, over which there seems to be a stable voltage of 1 mV when the button is not pressed, and a stable voltage of 4.8 V when the button is pressed.
To... |
H: Detect position of walkers along a path using IR transceivers
I am working on a project that the position of people walking along a path needs to be known. I'm a hobbyist so I don't know what options I may have.
I want to use IR sender and receivers to detect the position of people. I need to use around 20-25 s... |
H: Analog sensor reading and calibration
I have what I think is simple question regarding the use and data calibration of variable analog sensors (such as a force-sensing resistor). As more pressure is applied to this sensor, its resistance changes. This value can be collected by an Arduino device using the analogRead... |
H: Effect of BJT common emitter amplifier resistor(Rc,Re) ratios? How to select it?
Above is a part of a BJT common emitter amplifier with 15V Vcc(all caps ignored for DC). I was following a tutorial which explains how to setup parameters step by step. When explaining the DC biasing section, the tutorial first sets u... |
H: Gain of particular op-amp circuit (A combination of inverting, non-inverting and differential configurations)
I have a following circuit with an operational amplifier. It is a configuration I haven't seen before and I am not quite sure how to calculate the gain in terms of its inputs A and B.
The input B is just t... |
H: Verilog: How to avoid 'Redeclaration of ansi port'
I am trying to implement a start condition for i2c. And to ISim simulation I did. However, I keep getting this warning:
WARNING:HDLCompiler:751 - "timer_A.v" Line 40: Redeclaration of ansi port flags_timer_A is not allowed
WARNING:HDLCompiler:751 - "start_i2c.v" Li... |
H: What to do with USB power and ground when you have an external power supply?
I have a externally powered USB device. (It's actually my old VIC-20 computer, sort of)
USB data is handled by an ATTiny85. The USB interface is based upon the V-USB easylogger. The ATTiny85 receives inputs from the VIC-20 on three of i... |
H: Negative voltage using boost converter
I am referring a schematic where 16V,10.4V,-7v is generated from TPS61040
R12 and R17 are used to set 16V from TPS61040 IC and zener diode is used to generate 10.4V.
But how -7V is generated, I am not getting. Please someone guide.
Thanks.
AI: Think of it like a single-actio... |
H: CJMCU-75 -- seting the I2C adress
I just got embedded system CJMCU-75 which has LM75A I2C temperature sensor on top of it. I dig into the LM75A documentation and found out that it's I2C address consists of four fixed MSB and three LSB bits which can be set up externally by pulling pins A0/A1/A2 towards VCC or GND.
... |
H: How can I supply 5v voltage to circuit in a portable way?
I have made a circuit which needs 5v to operate, I want to give 5v supply to that in portable and compact way. I didn't find any battery with 5v specs. I managed to run it with 9v battery in combination with 7805 voltage regulator but that battery is too hea... |
H: Is there a typical 'ferrite' for use in a PCB?
I have a circuit diagram that I am trying to replicate (actually the Teensy 3.0/3.1 circuit diagram shown here https://www.pjrc.com/teensy/schematic.html) and there is a component called simply 'ferrite'. On the board it is a SMB component, maybe in a 1206 package but ... |
H: uC-controlled high-side switch
I designed a circuit that powers on when the car is started (key is in ACC or ON). The circuit's uC then enables 12V from the battery by setting port PC5 high. The uC detects when the key is switched off when port PC4 goes high via the opto-isolator and the uC then remains on until ... |
H: Charging two 12V lead-acid series batteries separately with one 12V solar panel
I am working on a senior design project and just wanted to ensure the following charge configuration would work. I have a 12V solar panel that I plan to run its' output to TWO separate PWM solar charge controllers. Despite the vehicle r... |
H: Demux realisation in hardware
Following the previous post
Output of XOR gate with high-impedance input
I am interested further how four-valued logic of SystemVerilog gets eventually implemented in hardware.
Could someone correct / confirm my next observations?
Consider
assign LED = (select) ? value1 : value2;
Ob... |
H: Please review my RGB Controller
First off, I just want to say that I'm still pretty new to PCB and schematics design, and electronics in general, so any suggestions on improvement are much appreciated!
I'm creating a basic circuit to control a string of addressable RGB LEDs. The circuit is powered by a 12v DC wallw... |
H: Is it possible to use an optointerrupter as a optoisolator?
I currently can't buy an optoisolator, so I was wondering if I could wrap a optointerrupter in tape to shield it from light and use that as an optoisolator.
Is this possible?
AI: Don't have an opto-isolator? Make one.
All transistors are photo-electric unt... |
H: Comparing current from two 9V batteries
I have two 9V batteries, an Energizer and a very cheap Gettop that was bundled with some equipment. The Energizer is down to 7.2V, the Gettop is at 9V. If I connect each of these separately to an LED via a 560 ohm resistor, the Energizer's current through the circuit is 7.1mA... |
H: Verilog: how to synchronously assign wire out with register?
This is the output of ISim simulation:
I want to decrease tx_data_ctr by 1 when flags_from_clk_div turns to 4'b0000 so sda_flag_from_transmit_byte take initial bit from tx_data[7:0]. However, I could not find a way to do it. What I actually ask is if the... |
H: Does magnetism affect the likelihood of an electrical arc occurring?
Would magnetism affect the likelihood of an electrical arc occurring?
AI: Yes, magnetism can and does affect arcs. Some large switches have permanent magnets to reduce arcing. This technique is more popular on DC, where arcing is generally worse.... |
H: Connecting Vcc pin to a logic gate
I have a sonar sensor which has 4 pins and may be due to a bug in my code, they are freezing in a few seconds after functioning. I found out if I reconnect the Vcc pin, they start working and yeah they freeze again. So I'm thinking rather than unplugging and plugging in the Vcc pi... |
H: Emulating Old Tektronix Coded Probes
I've got an older Tektronix 2430 100MHz oscilloscope. The older probes are "coded" and according to the manual are supposed to automatically select the proper scale based on the probe type. My last original probe just broke, so I ordered some inexpensive generic replacements. Th... |
H: Variable frequency AC power source
I'm looking for a variable AC power source for use in some electromagnetics experiments and longer term for testing inductors, transformers, core material frequency response, and that sort of thing.
I'm thinking my dream instrument would have voltage variable between 0-125V, be ca... |
H: Will this simple four n-channel mosfet H-Bridge Circuit work?
This is my H-bridge circuit without considering Back EMF. In the real circuit I would put four fast recovery diode to eliminate the Back EMF.Maybe schottkies?
Before I came up with this design , I googled "DIY H-Bridge". And I only found out H-bridge de... |
H: Powering cordless drill
So getting to the point. Ive got makita brushed cordless drill with dead batteries as those arent really cheap ive decided to try to power it through a microwave transformer. According to the switch it draws 12A at 12V. So after rectifying(kbpc2510) the 14V AC to around 12.2V DC i though th... |
H: Will any rom file for a Z80 computer work with any hardware?
A few months ago I made up some PCBs for a Z80 computer using designs from allthingsmicro.com
Unfortunately their website has been down and there seems to be no way of contacting them.
I have had the boards laying around for a few months and finally deci... |
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