hybridfree/eevblog-posts huggingface dataset:
IR-transparent potting compound? - Page 1
Forum section: electronics / projects

author: rea5245
author_rank: Frequent Contributor
timestamp: February 03, 2020, 10:12:21 pm
content: Hi,I'm looking for a potting compound that will withstand outdoor temperatures and moisture, while being transparent to IR light (850nm). A lot of epoxies don't seem to quantify their transparency in their datasheets. Can anyone recommend one?Thank you,Bob

author: rea5245
author_rank: Frequent Contributor
timestamp: February 06, 2020, 06:33:58 pm
content: Nobody??

author: Weston
author_rank: Regular Contributor
timestamp: February 06, 2020, 06:47:30 pm
content: A lot of epoxies are pretty chemically similar, so I would expect any transmission chart you find online to be somewhat applicable.850nm is close enough to the visible light range where any clear epoxy should pass 850nm with relatively little loss. I found this webpage via google which shows some transmission plots of epoxies and you can see they all extend decently far into the IR:https://www.masterbond.com/articles/optical-transmission-properties-adhesivesIf you want the epoxy to be opaque to visible light it might be a bit more difficult, you would probably have to source whatever dye they use in IR receiver components that absorbs only visible light and mix that into a clear epoxy.
IR Webcam -> Cooling? - Page 1
Forum section: electronics / projects

author: Lord of nothing
author_rank: Super Contributor
timestamp: June 08, 2016, 07:56:24 pm
content: I play around wiht my Webcam who have no IR Filter (and make sharp images!). The can get very Hot. I know hat Professional Thermal Cams have an Thermal Cooling inside.Does an Cooling bring anything?The Sensor is specified for"stable image: 0°C to 50°C junction temperature""sensitivity: 600 mV/Lux-sec"

author: Kleinstein
author_rank: Super Contributor
timestamp: June 08, 2016, 08:34:46 pm
content: With higher temperature the noise of the sensors increases. So a cold sensor can get away with less light.With the IR images there are two ranges of IR:1) near IR (e.g. 750-1050nm), which can still use SI sensors. So just a normal Si Sensor, just without the filter.These sensors work reasonably even without cooling. Cooed one might get away with less light.For the pictures one usually needs active IR illumination (e.g. LEDs). This is likely the sensor described.2) thermal IR (e.g. 5 µm -20 µm)These sensors really profit from a lower temperatures. Some even need it to work at all. These cameras can seen theIR radiation emitted at room temperature and similar. So no active light needed. Usually resolution is rather poor.The picture shows local temperature.Usually the sensor itself should not get that hot - it's more like the LEDs that get hot. So separating the LED light from the camera itself might already help.

author: Lord of nothing
author_rank: Super Contributor
timestamp: June 08, 2016, 08:46:21 pm
content: Its an "normal" USB Cam without an IR Filter.I just used a normal Candle.

author: Siwastaja
author_rank: Super Contributor
timestamp: June 09, 2016, 06:15:29 am
content: Webcam without an IR filter has absolutely nothing to do with a thermal camera whatsoever.Cooling the imaging sensor decreases the noise at long exposure times. With a video webcam, the exposure time is never very long, so the effect is probably negligible; the noise you see most likely comes completely from other sources.Peltier cooling of the CCD/CMOS sensor is used in contexts like astro photography where single frame exposures last for tens of minutes, if not hours.But you can try cooling to see if it decreases the noise. It is possible if the sensor is extremely low quality and running very hot for some reason.
IR2101 self-turn off behavior - Page 1
Forum section: electronics / projects

author: HalmondD
author_rank: Newbie
timestamp: November 25, 2024, 03:30:25 am
content: Hi, I designed a back 2 back mosfet circuit using IR2101 to drive it.That back 2 back mosfet will connect to 8 half bridge circuit through the Vout net. Using IR2104 to drive it. Those 8 hb is floating at the time of testing.The charge pump circuit run at 5Khz, and when I check the Voltage on bootstrap it's always high enough aroung ~10.5 to 11.5V, the Vcc is at 12V, and the logic input voltage is at 3.3V.I double check the Vgs of IR2101, it stay at 0V when I try to turn on the back 2 back mosfet at 100V while the bootstrap is at 11.5V, but when I try to do it at 50V, the Vgs work normally.After couple days of testing, we isolate the problem is between the connection of the back 2 back mosfet and the 8 half bridge, the charge pump and bootstrap circuit work perfectly, the problem only occure when we try to turn on the b2b while it is connected to the 8 hb mosfet. If it is Isolated from the 8 hb, the b2b work normally at any voltage even at 300V, but when I try to connect it to the 8 hb, it only work up to 80V, any higher than that and the b2b will not turn on at all.The reason for the b2b mosfet not turning on because the Vgs of the IR2101 refuse to turn on, it will stay at 0V only for voltage higher than 80V any other than that the vgs turn on perfectly.So we decided to isolate the b2b mosfet and the 8 haft bridge (hb), the Green line is a probe at point 1, and Yellow line is a probe at point 2, GND of the probe is also GND of the circuit. And the pink purple line is the minus between the Green and Yellow line.How do I know the Vgs of the IR2101 self-turn off, I isolate the the b2b with the 8 hb completly, the voltage now at 100V, when the 2 is isolate the b2b work normally, when I try to manually bridge the b2b and 8 hb, the vgs on the ir2101 drop suddenly, key word suddenly, straigh down to 0.If anybody has been working with the IR2101 and also having this problem please help me, I have been testing this circuit couple days and it is driving me crazy, I will accept any question and request for probing for further info on this ploblem, thanks in advance!
Ir2117 to drive buck converter problem  - Page 1
Forum section: electronics / projects

author: mah
author_rank: Newbie
timestamp: February 22, 2014, 11:21:50 am
content: i used ir2117 to drive mosfet for dc dc buck converter the input for the driver is pwm from microcontroller i attached the circuit but there is a problem the output from this driver is 9v pure dc not pwm like the input

author: mah
author_rank: Newbie
timestamp: February 22, 2014, 12:05:58 pm
content: so what is the solution?

author: mah
author_rank: Newbie
timestamp: February 22, 2014, 02:31:50 pm
content: lets talk about the last method using a transistor ? how to do this?

author: mah
author_rank: Newbie
timestamp: February 22, 2014, 03:40:50 pm
content: will BC549 be able to do this job as BJT? I also have IRFZ48 I need to adjust the configuration to work with.

author: georges80
author_rank: Frequent Contributor
timestamp: February 22, 2014, 03:56:18 pm
content: You need to firstly tell us what you are trying to do...What frequency and duty cycle are you planning to drive the FET? What is the FET switching (load)?Using a transistor as shown works fine to turn on the FET, but turnoff is based on the pullup resistor and most FETs have fairly high gate capacitance which means turns off time is slow such that the FET will spend time in the linear region. This may or may not be an issue depending on the frequency & duty cycle you are running at.cheers,george.

author: mah
author_rank: Newbie
timestamp: February 22, 2014, 04:49:11 pm
content: I am trying to drive n mosfet for buck converter that's all i want to do added to all previous talkduty cycle is changing from 0-90%frequency =100KHZ

author: georges80
author_rank: Frequent Contributor
timestamp: February 22, 2014, 05:05:40 pm
content: What's the load?A Buck needs a catch diode and also an inductor which aren't shown in your schematic. You would also need voltage sense back to the uC to regulate. Overall, using a uC to create a buck driver is not optimal since you have a slow control loop (software) and only 'digital' steps in adjustment (pwm duty cycle). Typically a 'real' switcher IC uses a saw tooth ramp and comparators to enable the duty cycle to be adjusted in much finer 'steps'.100KHz is relatively high, a npn with a pullup resistor will have quite slow turn off time and if the FET is switching high currents then the FET will dissipate more heat (loss) while switching off. You do realize FETs have high gate capacitance?Either choose a FET that can be switched at logic levels or find a driver that has logic level inputs. Or better yet, buy an off the shelf switcher IC.cheers,george.
IR2125 - Page 1
Forum section: electronics / projects

author: phenol
author_rank: Regular Contributor
timestamp: March 29, 2018, 07:37:39 am
content: I'm doing something with the IR2125 high side driver and i'm unable to find any mention in the datasheet of the highlighted pulse filter that's inside. It seems to function as a noise discriminator rendering the driver unresponsive to short glitches on the logic input. Now i need to know how short short is. In other words, what is the minimum pulse width i can use before it cuts out?I did find experimentally that it works with pw=60ns, but doesn't with pw=50ns or less...but that's on one part only at ambient temperature...

author: Sceadwian
author_rank: Unknown
timestamp: April 02, 2018, 01:31:15 am
content: Turn on rise time on page 6 might be pretty close to the number you're looking for which is 40-70ns depending on operating conditions.

author: phenol
author_rank: Regular Contributor
timestamp: April 02, 2018, 06:11:28 am
content: I would imagine that turn-on rise time and turn-off fall time are load (gate charge)- and output driver-dependent.My target was 50ns or less of output pulse duration, but as it stands today, the mosfet it drives is rather too large (slow) to respond properly even to 80ns at heavy (<20ohms) loads and supply voltage of 200V.
ir2153d/ir21531d transformer and mosfets - Page 1
Forum section: electronics / projects

author: paol
author_rank: Newbie
timestamp: July 24, 2020, 09:54:48 pm
content: HiAnyone with experience that can help matching mosfets and transformer primary (push-pull conf) inductance for best performance ?My schematic attached.Basically what I want is to carry input voltage of 24 to 63V (irs is powered from other power source 13V input) - then transformer is push pull (1:0.7 RATIO)Currently it is working with setup as on schematic - but it draws about 4W at idle (for me it is a little too much)Increasing working freq. for half bridge from 79kH to 98kH makes things worst (5W)I can prepare any transformer for this - but for now it is like (rewinding history)Also currently using 18mOhm (rdson) transistors - 200V .... so not cheap - I think all this stuff can be optimized to draw less power with cheaper transistors (safer higher voltage for DS and higher RDSon) but as I said ... currently rewinding history to optimize thisThanks for any help.

author: paol
author_rank: Newbie
timestamp: July 24, 2020, 10:02:11 pm
content: Alsoincreasing RDSon from 18mOhm to 140mOhm (mosfet) is lowering power usage - without load (from 4W to 3W) seems normal as there will be higher resistance when mosfet is on but also how power will be dissipated at mosfets...

author: paol
author_rank: Newbie
timestamp: July 30, 2020, 09:19:00 pm
content: Or maybee eliminate snubbers... cause they are 1WBut eliminating snubbers can make things worst - have some voltage spikes when switching and for 200V mosfets and +48V DC input sometimes it is 180V+ without snubbers so no margin - with snubbers there is not much ringing and no overshooting more than 110VAnyone have idea how to minimize ringing on that implementation ?Increasing rdson to 300-400mOhm and using 500V mosfets can allow me to resign from snubbers i think - but need to check thiscurrently waiting for other mosfets.But then I will need to rethink also mosfet heatsinks that currently are on PCB (more heat will be dissipated on fets)Or maybee someone have better idea how to controll push-pull transformer (cheap) - maybee self oscilating circuit with transistors ? but also I dont want to increase number of parts needed to solder...
IR4301 AMPLIFIER NOISE - Page 1
Forum section: electronics / projects

author: kiran_shrestha
author_rank: Regular Contributor
timestamp: August 18, 2014, 08:59:55 am
content: I have been designing class D amplifier using IR4301 class d amplifier IC but I have some problem, the out put is very much distorted and there some 30Khz repeative noise..What could be the problem ..

author: fcb
author_rank: Super Contributor
timestamp: August 18, 2014, 10:01:12 am
content: Post your schematic and as much information as possible (power supplies, scope traces of the noise etc...).

author: kiran_shrestha
author_rank: Regular Contributor
timestamp: August 19, 2014, 12:06:44 pm
content: I have used 18-0-18 transformer for the power supply and heres the schematic.. but i dont have osscilloscope..

author: kiran_shrestha
author_rank: Regular Contributor
timestamp: August 29, 2014, 04:03:19 pm
content: Here some short description of my project and circuit.http://shortedwire.blogspot.com/2014/08/class-d-amplifier-design-based-on.html
IR6500 v2 Upgrade - Page 1
Forum section: electronics / projects

author: tielko
author_rank: Newbie
timestamp: February 23, 2022, 06:50:38 pm
content: Hey guys I bought a BGA IR6500 v2 and rebuilt it a bit.I exchanged the 3 heating elements (Preheat) for 3x 600W Elsteine and the Top heat for a 200W Elstein. I also changed the relays.Now everything is top. Unfortunately, the Top Heat runs about 10-15 degrees.I tried to adjust or improve the PC410 PID Controller. Unfortunately without success.At the moment the following values are P=5 I=300 and D= 30I tried to adjust different values for 3-4 days. Unfortunately without success. It only gets worse but the heating is not faster or better.Does anyone have any experience of yours or a good idea?Thank you very much

author: daniellemill
author_rank: Newbie
timestamp: February 26, 2022, 06:33:17 pm
content: I have a similar issue! And the problem is almost the same! How to solve this problem?
IRC 10R 5905-66-012-6208 Adjustable Resistor - Help Datasheet - Page 1
Forum section: electronics / projects

author: Kitesurfing
author_rank: Newbie
timestamp: June 18, 2020, 06:14:53 am
content: Hi All,We have two IRC 10R 5905-66-012-6208 Adjustable Resistors, and don't know the rated wattage.Would anyone know the wattage or have the original datasheet.I tried IRC (TT) and had no response after a month.Any help would be great!!Thanks in Advance

author: eblc1388
author_rank: Frequent Contributor
timestamp: June 18, 2020, 12:20:58 pm
content: If in doubt, look for similar items to get a "feel" of its wattage.Luckily, a nice seller on ebay has listed a similar item specified at 11 Ohm, 6.2A, including the scale/dimension of the item.https://www.ebay.com/itm/Cenco-Laboratory-Slide-Rheostat-Variable-Resistor-11-Ohm-6-2-Amp-model-82910-14-/223231129624Check if the size of your adjustable resistor is similar to the listed item. If so, then you have the approximate wattage.

author: Kitesurfing
author_rank: Newbie
timestamp: June 30, 2020, 11:30:08 am
content: Thanks for suggestion. Based on that it approx 300W to 350W based on other similar Rheostats.I'm happy for the moment, but I'll leave this open just in case some has the actual datasheet just to be 100%.
irf7205 P-channel mosfet replacement (Qg vs Ciss) - Page 1
Forum section: electronics / projects

author: The Soulman
author_rank: Super Contributor
timestamp: June 01, 2016, 05:22:31 pm
content: I've blown a p-channel mosfet on my Lenz Compact (a digital model railway controller).This apparatus has a full h-bridge to output 19V ac (square wave) at about 16Khz at 2.5 amps (looking for more..).The top side uses (2x) IRF7205 (VDSS = -30V RDS(on) = 0.070ohm ID = -4.6A) and thebottom side uses (2x) IRLR024N (VDSS = 55V RDS(on) = 0.065ohm ID = 17A)Would like to replace the irf7205's wit something a bit beefier and similar spec as the irlr024n's.Also could use a TO220 instead of a SO8 device and put it on a heat sink so very low rds on is not that necessary,what is is the switching performance/speed dominated by (from my understanding) the gate chargeand gate capacitance.Been searching with the Infineon solution finder:https://www.infineon.com/cms/en/product/solutionFinder.html?channel=db3a30433cabdd35013ccebb4e4849ae#!Plenty of options to chose from with similar gate charge but most of them have a much higher gatecapacitance.Question: is the gate capacitance that important?http://www.infineon.com/dgdl/irf7205.pdf?fileId=5546d462533600a4015355f156091ae0EDIT:trying to figure out what gate drive voltage it uses I found out its the full supply voltage,originally 17.5 volt internally regulated but last year modified by me to 19.5 volt from a externallaptop psu.17.5 volts is close but acceptable for most mosfets, 19.5 volts is beyond acceptable and likely to have caused the failure.So two options possible, return it to it's original state and use a external (diy) booster,or still get the beefier mosfets and lower the supply voltage to about 18volts (burning some one and a halve volt with two diode drops?).Redesigning the drive stage is beyond feasible..

author: zlymex
author_rank: Frequent Contributor
timestamp: June 02, 2016, 06:44:02 am
content: Small gate capacitance will make the switching fast(in the case of PWM).Large gate capacitance may result in oscillation of the drive circuit if it is a close loop.I had some P-MOS such as IRF5210 and IRF4905, the later might be the smallest Rd-on for TO220 package.

author: The Soulman
author_rank: Super Contributor
timestamp: June 02, 2016, 08:29:02 pm
content: Quote from: zlymex on June 02, 2016, 06:44:02 amYes.Quote from: zlymex on June 02, 2016, 06:44:02 amYes and in my application, full h-bridge, if the bottom mosfet turns on before the top is fully turned off (because of to much gate capacitance) a so called "shoot trough" event occurs (also could happen the other way around of course)basically a power rail short circuit through two mosfets..In motor controller design something called "dead-time" is programmed to have some time betweenbetween switching off one mosfet and turning on the other.Quote from: zlymex on June 02, 2016, 06:44:02 amRd-on is for my application is the least of my worries, more worried about gate timing.Talking about opening a can of worms:http://www.digikey.com/en/pdf/v/vishay-siliconix/understanding-gate-chargeBetter read it a second time...Any more input much appreciated.
IRF7319 Latching Switch - Page 1
Forum section: electronics / projects

author: jwhitmore
author_rank: Regular Contributor
timestamp: December 13, 2016, 02:57:05 pm
content: I found this circuit  and implemented it on a PCB prototype but it just doesn't work at all. I've looked at Auto On/Off part of the circuit and whilst I can see what it's trying to do, the P-Fet Gate is always pulled high by a 100k Resistor so Auto on will never work. Can't see why there's a 0.1uF Cap in there.Ignoring Auto On/Off and looking at a button press I'm confused by what I'm seeing on the N-Fet Gate so I'm suspicious of the 10uF Cap as well. That N-Fet Gate is pulled high momentarily but then gets pulled down to -5V, which I don't have in the circuit? I've only got a 5V supply voltage connected so I'm impressed with -5V. (Have I discovered free negative energy? ;-)I'll attach a few scope traces. I'm happy with auto on output and auto off output as I don't see how they would work given the Cap. As for the button press output I've no idea what it's doing.Channel 1 / Yellow - P-Fet GateChannel 2 / Blue - P-Fet Drain Output of my latching switchChannel 3 / Pink/Purple N-Fet GateThere is another circuit on a forum post here  but it didn't include auto on/off circuit which I thought might be useful so I went with . Given that it's not working for me there is a chance I might learn something. There is a chance over Christmas holidays that I should bite the bullet and learn how to run SPICE on Linux.Thanks for any ideashttp://www.mosaic-industries.com/embedded-systems/microcontroller-projects/raspberry-pi/on-off-power-controllerhttps://www.eevblog.com/forum/projects/latching-switch/
irf9110? - Page 1
Forum section: electronics / projects

author: Rickv
author_rank: Newbie
timestamp: March 01, 2013, 12:24:26 pm
content: Hello Everyone. This is my very first posting on this board. I am a newbie to the electronics hobby and starting a very basic project that I have a question about. I am going to build (or at least attempt) Dave's soft latching circuit,http://www.eevblog.com/2012/03/30/eevblog-262-worlds-simplest-soft-latching-power-switch-circuit/, and have run into a snag. I live in a very rural area and parts are hard to find, I have found everything except the IRF9110, can a IRF510 be substitued?

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: March 01, 2013, 01:13:19 pm
content: Hi Rickv,The IRF9110 is a P.Channel MOSFET. The IRF510 is a N Channel MOSFET.Pretty much any P Channel MOSFET will work in the circuit, provided that it can handle the current.Regards,Jay_Diddy_B
irfp260n & lm317t from china real or fake? - Page 1
Forum section: electronics / projects

author: A7X
author_rank: Newbie
timestamp: January 03, 2019, 06:16:34 pm
content: My question is if these irfp260 and lm317t from China are real or fakes.for 10 pcs lm317 I paid 1 € and for 10 pcs irfp260 I paid 3.3 €.I have already tested the lm317 at 2a (works without problems )and the rds on the irfp 260 also looks real.sorry for my bad english

author: Benta
author_rank: Super Contributor
timestamp: January 03, 2019, 06:42:07 pm
content: I'm astounded that people buy this stuff, I'd never do it myself to save a few euros.I only buy from sellers with a documented supply chain = authorized distributors. The money saved brings 10 x the frustration.But OK, cheapness has no limits, I guess.

author: wraper
author_rank: Unknown
timestamp: January 03, 2019, 07:02:46 pm
content: LM317 is certainly fake, wrong ST logo. irfp260 regardless of being genuine or not are salvaged used parts.Leads are too shortand obviously retinned. EDIT: nope they are not too short but still they are at least retinned. Don't look like how they should be out of factory. Try bending the lead (front-back) while holding the case. If they are welded on, should break near to the case in wider part.
Irrigation Controller - Page 1
Forum section: electronics / projects

author: burko
author_rank: Newbie
timestamp: December 10, 2013, 12:22:33 pm
content: Just finished my irrigation controller design, build, and install. Take a look atwww.burkotronics.com.au

author: calexanian
author_rank: Super Contributor
timestamp: December 10, 2013, 10:56:28 pm
content: Looks good. Our company Alex-Tronix manufactures agricultural irrigation controllers. Ironically i am playing with that same SMPS module now for one of my next designs. The price for that module is less than my BOM in 1K quantities! (Shhhhhh.... Its not a real national part on there. ;-) Looks good. Whats the temperature sensor for? Freeze control? If you look up our patents you will see everything you need to make it self adjust the watering duration on a daily basis based on temperature alone. If you want I will dig up the numbers and you can get the math off off the document from the US PTO website.

author: calexanian
author_rank: Super Contributor
timestamp: December 11, 2013, 06:53:50 am
content: You may want to put mov's of lets say 47 volts across the solenoid outputs. Just another observation. Oh, and don't forget the freewheeling diodes on the relay coils. Forgive me if you already have those.

author: burko
author_rank: Newbie
timestamp: December 11, 2013, 10:10:59 am
content: Thanks for your comments.I did think about frost detection with the temperature sensor but I was also curious how hot and cold the board is getting in the solenoid valve box. I don't think temperature alone will give enough information for watering. During the summer it can be 35C here and have a thunderstorm in the afternoon with lots if rain. I have a weather station that the irrigation controller can access through the raspberry pi that will tell how much rain if any has been received. Perhaps this in combination with what you suggest would provide a good solution.As for freewheeling diodes the solenoids operate on 24VAC, therefore diodes across the solenoid would short for 180deg of the waveform.

author: calexanian
author_rank: Super Contributor
timestamp: December 11, 2013, 08:20:07 pm
content: The diodes are on the relay coils. The mov's are across the solenoids. You will find a valve box in spring and summer tracks ambient temperature rather well. A small correction factor is usually all that is required. In winter things change a bit.
irs2153 - Page 1
Forum section: electronics / projects

author: ant17
author_rank: Regular Contributor
timestamp: September 02, 2013, 11:01:07 pm
content: hi guys can anyone tell me from the attached datasheet is bipolar power supply required

author: Harvs
author_rank: Super Contributor
timestamp: September 02, 2013, 11:15:12 pm
content: To do what? This is nothing more than a highside / lowside FET driver with integrated oscillator... Are you planning on doing something other than the example circuits in the datasheet?

author: ant17
author_rank: Regular Contributor
timestamp: September 02, 2013, 11:20:26 pm
content: drive a igbt halfbridge to switch a inductive load

author: Experimentonomen
author_rank: Regular Contributor
timestamp: September 03, 2013, 03:55:14 pm
content: Its just your standard halfbridge driver with a built in ne555 like oscillator, so just hook it up as per the application example in the datasheet and select a rt and ct that suit your operating frequency range.
Is 1n4148 suitable for bootstrap diode application? - Page 1
Forum section: electronics / projects

author: hbozyq
author_rank: Contributor
timestamp: May 28, 2023, 05:01:50 am
content: Just as title. I'm trying JLC SMT pre-assemble service and for saving money I'm going to use basic parts only.For my application I got some N-MOS half bridges and now a bootstrap diode should be choose.The bus voltage is 60V max and switching frequency is less than 50khz.I got two choice: US1M(1.7V@1A 75ns) or 1N4148WS(1.25V@150mA 4ns).The first one is fine for I had use it before, but its footprint is a bit too large.So I wonder if 1N4148 is capable for my application, seems like the main issue could be its relatively small current capacity.Any suggestions? Thanks in advance.

author: Terry Bites
author_rank: Super Contributor
timestamp: May 28, 2023, 06:27:51 am
content: Read dis

author: Vovk_Z
author_rank: Super Contributor
timestamp: May 28, 2023, 06:34:40 am
content: Quote from: hbozyq on May 28, 2023, 05:01:50 amI don't clearly understand what your circuit is but you may want consider peak reverse voltage too. It may be 2x-3x bigger of an input voltage so 100V rated 4148 (4448) may feel not good.

author: hbozyq
author_rank: Contributor
timestamp: May 28, 2023, 07:06:51 am
content: Let me clarify it. The circuit is like this.BTW I found this:The chosen bootstrap diode (DBS) should be rated higher than the maximum rail voltage since the diode must be able to block the full rail voltage and any spikes seen at the VS node. The diode’s current rating is simply the product of total charge (QT) required by the HVIC (High Voltage Integrated Circuit) and the switching frequency. An ultrafast recovery diode is recommended to minimize any delay of charging the CBS cap. A 1A ultrafast recovery diode is typical for DGD2103M applications.(Diodes, AN1154)So I guess 75V will be fine? Using a very high voltage rating diodes will no be really helpful for MOS will break down first.

author: David Hess
author_rank: Super Contributor
timestamp: May 28, 2023, 08:14:36 am
content: The 1N4149 is higher current than the 1N4148. The BAV20 or BAV21 is higher voltage but still pretty fast. There is probably some bipolar transistor collector-base junction which would be better than either, but they would need to be qualified for recovery time.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 28, 2023, 01:50:14 pm
content: Fine on average current to most bootstraps, but the catch is pulsed current. I would want to see a 10 ohm series resistor with the diode. And, if that configuration gives adequate charge time and average output current/voltage, then that will do.Tim

author: hbozyq
author_rank: Contributor
timestamp: May 28, 2023, 03:33:49 pm
content: Thanks. Definitely will try it.

author: hbozyq
author_rank: Contributor
timestamp: June 03, 2023, 12:45:05 am
content: Tried this in the field, using a 10 ohm series resister with 1n4148ws, the circuit work as expected without issue.
is 2.5V 700F super capacitor enough for spot welding? - Page 1
Forum section: electronics / projects

author: Porama6400
author_rank: Regular Contributor
timestamp: April 03, 2018, 11:52:24 am
content: I want to build my own spot welderI saw 700F 2.5V super capacitor sell at local store, I wonder if it is enough for spot welding,also is few 20A relay enough for switching on output?I don't have much knowledge about (very) high current circuit.Thank you.

author: KhronX
author_rank: Frequent Contributor
timestamp: April 03, 2018, 12:15:01 pm
content: I wouldn't exactly trust mechanical switching (relays or solenoids) for such high current DC loads.AvE over on Youtube did some experiments in that directiona while ago, but that's more in the "quick and (very) dirty" category, imhoI'd much rather go with something like a bank of beefy MOSFETs scavenged from dead ccomputing equipment (think mainboards, beefy graphics cards, etc).Those are used exactly in those roles - switching large currents (in the double or even triple digit range) at low voltages (1V or so).
Is a DIY home alarm panel a difficult project? - Page 1
Forum section: electronics / projects

author: e100
author_rank: Frequent Contributor
timestamp: August 11, 2022, 09:23:44 am
content: The commercial offerings all seem to be based on ancient technology with hacked add-ons to provide wireless and internet connectivity etc.In the case of my Bosch alarm it's cellular comms module periodically gets confused and the whole thing has to be power cycled to bring it back to life, then I have to manually reset the clock because it doesn't have a battery backup and it doesn't know how to get the time from the internet - unbelievable!From tinkering all I can gather is that the sensor inputs do loop resistance measurements to detect tampering/open circuit, short circuit and alarm conditions. The alarm outputs also do loop resistance measurements to detect tampering.Is that basically it? The logic doesn't seem particularly complicated, although the Bosch programming app makes it look complicated.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: August 11, 2022, 09:47:06 am
content: Quote from: e100 on August 11, 2022, 09:23:44 amI don't know about your jurisdiction but I know there are rules here for how long the alarm can sound outdoors, and repetitious false alarms.Check the sim card/connections on the comms unit.
Is a DIY satellite dish worth to have ??? - Page 1
Forum section: electronics / projects

author: Dhanushka
author_rank: Regular Contributor
timestamp: November 03, 2020, 09:51:03 pm
content: Hi,I am trying to make an more than 6 feet DIY KU band satellite dish for a FTA receiver from south Asia to detect long distance FTA services. Is this idea is good and please suggest me good tutorials if you know.Thanks

author: ChristofferB
author_rank: Frequent Contributor
timestamp: November 04, 2020, 10:05:40 am
content: I have seen a few people making rather nice large parabolic dishes by covering a large round opening with aluminized mylar and then drawing a vacuum behind it, sucking it inwards. I've always found that pretty interesting.But aside from that; dishes are plentyful all over the world and are likely being scrapped in the thousands every day. If you have access to a local scrapyard you might be able to simply buy one for a bargain

author: S. Petrukhin
author_rank: Super Contributor
timestamp: November 05, 2020, 11:57:18 pm
content: A long time ago, I made out of styrofoam. I glued several pieces into a cube, cut off one side as a sphere, pasted foil, cut a tunnel on the other side and placed the receiver there.
is a lithium monoflouride battery a leak hazard? - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: June 26, 2022, 10:58:25 pm
content: I learned there is a lithium monoflouride battery in my VNA. It sounds bad.Is this a leak hazard? My 8350B got thrashed by a rechargeable AA leak inside (two units got damaged, from two units I made one unit). Casualties included cable harness for the module, rusty switch plates, GPIB card, Power Supply card and some how processor board and the mainboard (which I repaired by using new solder resist but too many parts are broken to bother with fixing the 'parts' unit). I don't want a repeat of this shit show with the rest of the VNA...so.. is lithium monoflouride evil?

author: David Hess
author_rank: Super Contributor
timestamp: June 27, 2022, 03:51:10 am
content: I do no think you have anything to worry about. The common lithium primary cells should never leak unless physically damaged or charged, at least within their operating life.

author: coppercone2
author_rank: Super Contributor
timestamp: June 27, 2022, 07:05:13 am
content: I saw some corrosion around a LR6 lithium thionyl chloride cell before I think, but it was very minor (on the leads and the desoldering process smelled a little funny when I desoldered it). Thought flouride might be worse. Seems rare.
Is a single NTC thermistor enough for motor soft start? - Page 1
Forum section: electronics / projects

author: analogo
author_rank: Regular Contributor
timestamp: May 31, 2020, 04:27:18 pm
content: I would like to limit the inrush current of a water pump. It is working fine up to now, but I can hear how violent the initial impulse is.Reading around I have found that the most basic way to implement a soft start is a NTC thermistor. But I haven't found any application note that deals with simple cases like mine.Here is the my trivial circuit:https://crcit.net/c/38a809a8be3c4096a4255481784daee1(The capacitor is there to block EMF.)Would such a trivial circuit be OK?How can I determine the right Ohm value for the thermistor?

author: Benta
author_rank: Super Contributor
timestamp: May 31, 2020, 06:27:00 pm
content: It must be an extremely small pump with a 4.7 k NTC. As such, start current should not be an issue.

author: analogo
author_rank: Regular Contributor
timestamp: May 31, 2020, 06:39:49 pm
content: Benta, that was just a diagram, I have no idea which value the NTC should have.The (el cheapo) motor is consumes ~ 1A (24V) in steady state, and about 1.5A when it starts up.Is there a rule of thumb for which Ohm value the NTC should have for such a motor?In addition to the inrush current, I would like to use the soft start to avoid the initial transient wave of water that violently shakes the pipes.

author: Kasper
author_rank: Frequent Contributor
timestamp: May 31, 2020, 07:06:39 pm
content: Not sure how to use a thermistor for this but you could connect switch through RC delay circuit to transistor to slowly turn it on.

author: TimFox
author_rank: Super Contributor
timestamp: May 31, 2020, 10:14:09 pm
content: When using a NTC thermistor to limit starting current, you must remember that it may not cool off sufficiently between power-ons, if you need to start and stop the load repeatedly.

author: Benta
author_rank: Super Contributor
timestamp: June 01, 2020, 04:28:12 pm
content: Quote from: analogo on May 31, 2020, 06:39:49 pmSo now the motor is not 12 V, but 24 V. It consumes 1 A steady state. Why didn't you post this information in your original question? Talk about wasting people's time.1: get the facts together2: present them in an orderly way3: ask your questions.How hard can it be? Jeez...

author: trobbins
author_rank: Frequent Contributor
timestamp: June 01, 2020, 11:47:51 pm
content: Part of your preparation should be to obtain a scope plot of the inrush current response. An NTC is rated to absorb a certain level of energy during the initial transient event, and a datasheet would provide an example of that energy capability in the form of charging up a capacitor (as that is the most common usage).Another part of the prep is to determine what minimum current is needed to start the motor, as it may be that even using a constant current power supply, the start-up current required must be larger than the steady state current, so you won't be able to insert more than a certain maximum series resistance.
Is a voltage follower really simple? - Page 1
Forum section: electronics / projects

author: PythonGuython
author_rank: Contributor
timestamp: September 10, 2020, 12:21:56 am
content: Hello I'm somewhat new to electronics and I've been designing a vocoder. Right now I've been working on a voltage follower that will provide the control voltage to my voltage controlled amplifiers in each frequency band. Is a voltage follower as simple as a rectifier? Or maybe a rectifier would lag the voltage too much? Let me know if the question is not clear.

author: OM222O
author_rank: Frequent Contributor
timestamp: September 10, 2020, 01:06:27 am
content: rectifier is not a voltage follower at all! just google op amp voltage follower, any op amp should be able to take care of audio frequencies without an issue.

author: ledtester
author_rank: Super Contributor
timestamp: September 10, 2020, 01:08:42 am
content: QuoteA "voltage follower" can have various implementations but usually doesn't involve a "rectifier".This page talks about an "envelope follower":https://www.instructables.com/id/Build-an-analog-vocoder/Is that what you are referring to?

author: PythonGuython
author_rank: Contributor
timestamp: September 10, 2020, 02:54:57 am
content: Yes that is what I meant, sorry! Not a voltage follower, an envelope follower
Is air conditoner's has a starter capacitor. - Page 1
Forum section: electronics / projects

author: sfiber
author_rank: Regular Contributor
timestamp: June 20, 2014, 08:01:43 am
content: Hi friends.There is a question for you.I have an air conditioner in my room and there is a little problem with it.Problem is exactly like this;when I connected my ac to wall plug,it needs a little time to start.Actually for a couple of minutes it doesnt respond to remote controllers order and then after 3,4 minutes it starts to work correctly.Then I turn of to ac but not disconnecting from wall plug it can be start whenever I want.I think this problem is about starter capacitor if it has.

author: Psi
author_rank: Super Contributor
timestamp: June 20, 2014, 09:28:14 am
content: Some AC units wait a few minutes for the box outside the house to start pumping refrigerant before the inside unit starts working.

author: sfiber
author_rank: Regular Contributor
timestamp: June 20, 2014, 09:48:52 am
content: Quote from: Psi on June 20, 2014, 09:28:14 ambut it doesnt responde to anything.No one of the lights on until pass 2 or 3 minutes.

author: SeanB
author_rank: Super Contributor
timestamp: June 20, 2014, 06:00:56 pm
content: Likely the remote receiver has a dying power supply inside it. A motor capacitor failing will mean the motor will try to start then trip out from overcurrent. The capacitors inside the remote receive will work after a fashion after they heat up from the current flowing through them. Eventually it will stop working altogether.

author: Po6ept
author_rank: Regular Contributor
timestamp: June 20, 2014, 10:59:57 pm
content: Many air conditioning units have a built in time delay to prevent a compressor stall. If the unit is turned off and on too quickly, the freon that has been compressed into a liquid will still be inside the compressor. When the compressor tries to start, it is trying to compress that liquid, causing stress on the unit and excess current draw. Delaying the start provides time for the compressed refrigerant to bleed through the expansion valve and turn back into a gas. The time delay is activated at startup and if you lower the thermostat setting immediately after the compressor stops.This might not be true of your unit but most modern air conditioners have this feature.
Is analytical sensitivity analysis still being used? - Page 1
Forum section: electronics / projects

author: Joe M
author_rank: Contributor
timestamp: April 13, 2022, 04:25:45 pm
content: Is analytical sensitivity analysis still relevant for anything other than the simplest of circuits? and by that I mean, are people still doing partial derivatives and so on? or have we reached a point that it all just boils down to lots of Monte Carlo analysis runs?
Is any free signal integrity simulation tool ?  - Page 1
Forum section: electronics / projects

author: Miyuki
author_rank: Frequent Contributor
timestamp: May 05, 2016, 09:40:57 am
content: HiI want to make some experiments with FPGAs and RAM, just on two sided board and packages with leads to easy work, but want frequency in 80-160MHz rangeIs here any good free toll to simulate signal paths ?

author: danadak
author_rank: Super Contributor
timestamp: May 05, 2016, 10:19:01 am
content: Several FPGA vendors offer free timing tools in their suite,Xilinx, Altera come to mind.Regards, Dana.

author: AndyC_772
author_rank: Super Contributor
timestamp: May 05, 2016, 10:36:42 am
content: FPGA vendors' free tools are for timing analysis of their devices, but they won't tell you anything about the integrity or timing of the signals on the PCB outside of their chip.To simulate signals on the PCB you need a tool like HyperLynx, which isn't free. As far as I know, there are no free tools that do this.
Is any SMPS feedback loop compensation calculator ?  - Page 1
Forum section: electronics / projects

author: Miyuki
author_rank: Frequent Contributor
timestamp: March 21, 2016, 09:55:12 am
content: Hi,I want to askIs any free tool to calculate SMPS feedback loop (gain, phase, margin ... in all load modes)?I build here one small SMPS for amplifier +- 23V, simple design with tl494, single transistor forward, 230kHz and tl431 with optocoupler at feedbackAs a lazy creature I want just to put values to calculator (Inductor, Capacitor and load range) and get compensation networkDoes anyone created it already ?

author: batteksystem
author_rank: Regular Contributor
timestamp: March 21, 2016, 10:10:36 am
content: It is quite common for the IC company to provide the calculator in excel for you to calculate the required inductance and capacitance at a given switching frequency and ripple requirement. For example, I know that the onsemi NCP3063 provide such tool for me to estimate the values before really do verification with real PCB. However, this is usually IC specific.Another way is to construct a simulation circuit yourself using pspice. Quite time consuming, and I rarely did it nowadays.

author: Miyuki
author_rank: Frequent Contributor
timestamp: March 24, 2016, 07:42:14 am
content: So i found what I'm looking forComponent Selection: Type II Loop CompensationandComponent Selection: Type III Loop Compensationwith nice explanation of power stage transfer function at all topologieshere

author: diyaudio
author_rank: Frequent Contributor
timestamp: March 24, 2016, 10:34:19 am
content: Quote from: AcHmed99 on March 21, 2016, 10:22:08 amwhy doest a hystertic controller need compensation ?

author: diyaudio
author_rank: Frequent Contributor
timestamp: March 24, 2016, 11:54:25 am
content: Quote from: AcHmed99 on March 24, 2016, 11:21:32 amThanks, will look into it.It says its a Microsemi Proprietary Hysteretic Control.. that explains alot.

author: Warhawk
author_rank: Frequent Contributor
timestamp: March 24, 2016, 02:44:06 pm
content: OT:I am better wondering why Microsemi has the TN-203 Preliminary / confidential on the webAbove that when you google for TN-203 it is a completely different appnote.End of OT

author: samofab
author_rank: Regular Contributor
timestamp: March 24, 2016, 04:17:41 pm
content: Hello,I have a related question:If you are designing a general purpose lab power supply: what are reasonable edge cases (maximum capacitance, indutance,...) against which to design the feedback loop?
Is anyone devoloping for ios or android using Qt? - Page 1
Forum section: electronics / projects

author: Valueduser
author_rank: Contributor
timestamp: November 20, 2013, 01:24:46 pm
content: I just started a small desktop application project that will be targeting windows and osx platforms using the Qt framework. Has anyone here begun using it for android or ios? I am interested in interfacing some hardware projects with mobile devices but would like to use c++ (rather than java or objective C) to create the gui. I was just wondering if anyone could offer first impressions of the android/ios support of the tech preview in Qt 5.1.

author: amyk
author_rank: Super Contributor
timestamp: November 21, 2013, 12:08:25 pm
content: Based on past experience (and some recent reviews) Qt is annoying slow and resource-intensive...

author: Valueduser
author_rank: Contributor
timestamp: November 21, 2013, 01:35:54 pm
content: Quote from: amyk on November 21, 2013, 12:08:25 pmThat's too bad, I'm really enjoying using Qt for desktop development. Hopefully they can work out the bugs, being able to develop a GUI across different platforms is very attractive to me since It's not really my main area of focus.
is anyone interested in an Eagle version of uCurrent? - Page 1
Forum section: electronics / projects

author: iontodirel
author_rank: Contributor
timestamp: October 12, 2017, 07:22:29 am
content: Not finished yet, but almost there

author: danadak
author_rank: Super Contributor
timestamp: October 12, 2017, 09:41:35 am
content: Yes to interested.Are you going to post layout ?Regards, Dana.

author: Gyro
author_rank: Super Contributor
timestamp: October 12, 2017, 10:55:28 am
content: As you're making the effort, you could take the opportunity to fix and improve it:- Add footprints for inverse parallel protection diodes across the input.- Use a rotary switch and include additional current shunt resistors (one per decade) to ensure that you always achieve minimum voltage drop and maximum accuracy.Edit: Possibly add a footprint for a capacitor to improve noise / stability. I can't remember the exact position or value but you can find it in one of the uCurrent threads.

author: iontodirel
author_rank: Contributor
timestamp: October 12, 2017, 10:08:38 pm
content: Quote from: danadak on October 12, 2017, 09:41:35 amDana, yes, I will post on github as soon as it's done, I'll be sure to let you know

author: iontodirel
author_rank: Contributor
timestamp: October 12, 2017, 10:11:24 pm
content: Quote from: Gyro on October 12, 2017, 10:55:28 amThanks. I'm a software engineer not an electronics engineer, there's only so much I can do for nowbut, the first things I'd like to improve is the battery life (using a larger coin cell), second would be the battery indication, I want green for on, and yellow for low battery (with one at a time obviously). I do agree that the switches are annoying. That's something I also want to improve.

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: January 30, 2018, 12:25:22 pm
content: HI,Have you made any progress ? I would be interested by the eagle files.