hybridfree/eevblog-posts huggingface dataset:
Lowest wattage 82V MR-16 bulb - Page 1
Forum section: electronics / beginners

author: BeBuLamar
author_rank: Super Contributor
timestamp: February 15, 2024, 11:28:43 pm
content: I have a number of Kodak Carousel projector which uses 82V 250-300W bulb. I want to convert one of them to a slide copying device. I am looking for the lamp bulb that I can install in the projector as it but has much lower wattage like 50W or so. I need to diffuse the light and the 250W bulb would melt my diffusing plastic. There are many low wattage MR16 bulb but they are 12V or some low voltage and not 82V.

author: CaptDon
author_rank: Super Contributor
timestamp: February 16, 2024, 03:17:16 am
content: I never realized the bulb was 82 volts?? I have an old Kodak carousel unit and it gets so hot you can't even touch the chassis until you run just the fan in cool down mode!!! I have around 6 carousels of family slides to transfer to DVD. The advance mechanism is dead!! It is made of teflon or nylon and the makes them brittle and they break. I swear the projector was built around the advance mechanism as it is a P.I.T.A. to repair and adjust!!!

author: jwet
author_rank: Frequent Contributor
timestamp: February 16, 2024, 01:59:15 pm
content: There are 120v MR16 bulbs in halogen and led. Feeding them with lower volts will lower their output. Both halogen and LED have a tendency to reach a threshold where the produce approximately the same color.

author: BeBuLamar
author_rank: Super Contributor
timestamp: February 16, 2024, 02:45:06 pm
content: I will try this bulb. 5000K is better than the 3200K halogen that is in the projector now.https://www.amazon.com/Light-Dimmable-Daylight-Replace-Halogen/dp/B09KQR5N2H/ref=sr_1_24?dib=eyJ2IjoiMSJ9.-RHNGKSjz4AGne00A1Gi8N-tYKK46obki9RxvHYR7jTXQ3lKskiohmBAPG8D_J1-VE_fPPRjUKh2dkAMD6EKqusmQ27KfNOp11gOj3aiqcSCpf25e3IKHKV3wLR4KmZQv88yU9oEX_wnKY0BT3UnD63HEIKIBSu2YkJrgGeHl4XivNfHXFSmrUal8UoDzHocTNKFkaysxImmgcOcOcq9FIsgVGpOa4_Xx8Yw9umxDTnbNOVzxZ5zT3_150aXiNRh3va9pL_cryQI2PonFjLw5ImJ7tH-mJqp44OV0-Ix9xg.lou6aodHp8m-QJLDxfFwX7-SrQWndZnGA9amJaamno8&dib_tag=se&keywords=mr16+led+120v&qid=1708094523&sr=8-24

author: jwet
author_rank: Frequent Contributor
timestamp: February 20, 2024, 01:23:54 pm
content: Post a summary of what you learn please- I'd be interested to know how well this worked for my own knowledge.
Low/zero current indicator, switched on direct from ATmega?  - Page 1
Forum section: electronics / beginners

author: mortrek
author_rank: Contributor
timestamp: July 27, 2019, 09:04:29 pm
content: I wanted to create a 'low battery' indicator for an ATmega328p in a very low-current setup that runs from alkalines and spends most of its time in sleep mode. I was thinking that during some wake cycles, it could check an ADC connected to the battery source (hopefully it's really low leakage...), and if it's below a certain threshold, switch some indicator on that takes basically 0 power to maintain. Something like a latching relay, but an indicator. It could be a small white/red dot, or something similar, I don't care. Something very simple, and takes like 1 digital output to switch it on from an ATMega, preferably directly from the pin (so, very low current). I'd prefer to switch it off manually with a button or something. I don't care if it's 1mm in diameter, it just needs to be visible. It needs to stay indicating when power is removed.To be clear, I just want a the lowest-current low-battery indicator possible, to indicate the capacity without draining the batteries unnecessarily. If something discrete from the MCU would work for that purpose, I'm fine with it. The battery setup is 3 alkalines in series, so ~4.5V nominal to about ~3V cutoff, but I want the indicator to 'indicate' closer to 3.3-3.6V.Is there a name for this type of thing that I should be searching for? I'm trying different permutations of keywords and just getting a lot of other stuff.edit:Ok I've found flip dots... I forgot those existed. I'll look into those further.edit2: Do they make flip dots / flip discs that use <40mA and activate with <=3V?

author: ledtester
author_rank: Super Contributor
timestamp: July 28, 2019, 01:09:41 am
content: This project is using small pager motors to create DIY flip dots which can be powered with < 3V:https://hackaday.io/project/18541-dot-flippers/log/62647-progress-in-diy-flip-dots
LP Filter component selection - Page 1
Forum section: electronics / beginners

author: tyguy2
author_rank: Unknown
timestamp: June 04, 2017, 04:54:39 am
content: I'm attempting to remove some of the high(ish) frequency noise (15khz-20kHz) on some speaker lines, and I've decided to use a low pass filter with a capacitor and resistor. The issue arises when selecting components. The speaker is about 400 watts, and I need to make sure I don't burn out the resistor or cap. The peak voltage of the speaker should be somewhere between 40 - 50 volts, and I'm not sure if I should you low value resistor and high value capacitor or visa versa. I'm fairly sure that the higher value resistor I use, the lower the maximum volume of the speakers will be. Any ideas? I feel like this should be a pretty simple V=IR and P=I2R calculation, but I don't want to end up burning something down. Thanks in advance!

author: MrAl
author_rank: Super Contributor
timestamp: June 04, 2017, 06:14:51 am
content: Quote from: tyguy2 on June 04, 2017, 04:54:39 amHi,Of you tried a 0.1 ohm resistor and 100uf cap, the cut around 15kHz would be about 3db, but then the load on the amplifier would be too great at say 20kHz. If you go up in resistance you loose top end power performance, thus i dont think it is possible to use an RC filter here with this much power. Maybe an LC filter.Alternately you may be able to use a shunt RC filter, but you have to watch out for the extra loading this causes on the output of the amplifier.

author: ruairi
author_rank: Frequent Contributor
timestamp: June 04, 2017, 06:43:27 am
content: Is the noise being picked up between the amplifier and the speaker? (this is reasonably rare IME). If not why not filter the line level signal before the amp?

author: tyguy2
author_rank: Unknown
timestamp: June 05, 2017, 02:12:46 am
content: I completely forgot about using an inductor. I think I'l try out an LC filter and let you all know how it goes. I can work the math from here.
LPA schematic - Page 1
Forum section: electronics / beginners

author: dberryco
author_rank: Newbie
timestamp: December 14, 2022, 06:21:31 pm
content: Briefly, I'm looking for some plans/schematic to build a variable 100V 10A DC linear power supply with a very clean, stable, low noise output.I'm a retired electronics technician (USAF ground radio) and have no trouble building or troubleshooting most anything that smokes when you poke it wrong. I'm not looking to reinvent the wheel here; I'm just having trouble finding a decent schematic and parts list. I know I can buy a PS but the good ones are expensive, and I don't need a computer interface, digital controls or anything fancy. It sounds like a fun project as well.I have 110/220 60Hz voltage available.

author: jwet
author_rank: Frequent Contributor
timestamp: January 18, 2023, 05:45:23 am
content: I'm responding because I can see that you've gotten no responses. Your specification is the problem. If you want to make a 0-100V "linear" power supply, you would be dissipating a kilowatt at the bottom end- this is not so practical. Commercial supplies would likely use a multitap transformer with relays to get the dissipation down to something reasonable, < 100 W. HP made big supplies like this that used SCR's driving the primaries of the main transformer to keep class A type power dissipation down. A pure linear supply just doesn't make sense. Think through your needs and refine your spec a bit. You can buy commercial supplies that can do but they're likely worth the money- its not an easy problem. Are you sure you need Zero to 100V at 10 amps??
LPF behavior - Page 1
Forum section: electronics / beginners

author: BorisRap
author_rank: Contributor
timestamp: February 26, 2024, 10:09:45 am
content: Hi guys,I'm trying to simulate a circuit I have to build. I have a pulsing current source of amplitude 1mA and duty cycle 50%. The frequency of this source will vary from DC to 1Mhz.Just to test I put together this circuit in LTSpice to check the behavior.I set a low pass filter to around 33Hz, the rest of the filtering can be done digitally.I simulated the frequency at 1Khz and 1Mhz and I found that the output voltage of the opamp is the same (500mV).1Khz:1Mhz:Why is that? I thought the output at 1Mhz would be way lower due to the LPF.That is actually the behavior that I want for my circuit, but I just can't understand why isn't being attenuated at higher frequenciesThanks!

author: Zero999
author_rank: Super Contributor
timestamp: February 26, 2024, 10:19:45 am
content: Your low pass filter is working. It is attenuating the high frequency AC components of the signal and allowing through the DC.The input signal is 1V square wave, with a 50% duty cycle, which is equivalent to 0.5VDC plus a 0.5V bipolar squarewave (i.e. going from +0.5V to -0.5V) superimposed on top of it.Refer to the simulation below.V3 = V1+V2Therefore:squarewave1 = squarewave2If you add a low pass filter, it will remove V2, which is entirely AC, leaving only V1. A high pass filter will have the opposite effect and you'll be left with a bipolar 0.5V squarewave.

author: BorisRap
author_rank: Contributor
timestamp: February 26, 2024, 10:54:48 am
content: Quote from: Zero999 on February 26, 2024, 10:19:45 amThanks for the explanation!

author: radiolistener
author_rank: Super Contributor
timestamp: February 26, 2024, 11:04:33 am
content: Quote from: BorisRap on February 26, 2024, 10:09:45 amBecause DC voltage (500mV in your case) is 0 Hz frequency which is below 33 Hz cut-off of your LPF, so it is passed through filter with no attenuation
LPF question - Page 1
Forum section: electronics / beginners

author: stoica adrian
author_rank: Contributor
timestamp: July 13, 2018, 03:00:38 am
content: Hello,I have two qestions, if you can help me.What happens after you pass the 3db point of a LPF, and witch is the maximum ° that you can obtain with a LPF?

author: Bassman59
author_rank: Super Contributor
timestamp: July 13, 2018, 03:49:04 am
content: Quote from: stoica adrian on July 13, 2018, 03:00:38 amPass it from which side? To the right (increasing frequency) of the 3 dB point, the response increases towards unity, at which point it flattens out. To the left of the 3 dB point, the response decreases with a slope given by the number of poles in (the order of) the filter. One pole, your attenuation goes as 6 dB/octave. Two poles give an attenuation of 12 dB/octave, and so forth.QuoteThat too depends on the order of the filter.

author: Circlotron
author_rank: Super Contributor
timestamp: July 13, 2018, 04:09:56 am
content: RC low pass filter output would approach 90 deg phase lag, I expect.Probably never quite get there.

author: David Hess
author_rank: Super Contributor
timestamp: July 13, 2018, 11:45:07 am
content: 90 degrees maximum per pole or order.

author: Audioguru
author_rank: Super Contributor
timestamp: July 15, 2018, 03:51:03 pm
content: A single R and a single C makes a very poor filter. it rolls off at only 6dB (half the level) for each octave (10 times the frequency). Use an opamp or a few to make a multi-order active filter.

author: Wimberleytech
author_rank: Super Contributor
timestamp: July 15, 2018, 04:25:36 pm
content: Quote from: Audioguru on July 15, 2018, 03:51:03 pmI know you meant "octave (two times frequency)"
LSM9DS1 Error? Broken? - Page 1
Forum section: electronics / beginners

author: Lydsius
author_rank: Newbie
timestamp: July 20, 2020, 03:09:54 am
content: Hello everyone, thanks for reading my first post. Long story short, I'm using a LSM9DS1 accel/gyro/magnetometer for a project. I've fabricated a custom PCB, and got one working on the first revision. Now I can't seem to get the LSM9DS1 working on the second revision. I am using a hot air gun, cheap solder flux, and solder of course to attach it (I don't have solder paste). Whenever I try to access the "who am I register" for the accelerometer and magnetometer the device returns 0x38 and 0x10 when it should return 0x68 and 0x3D. It also doesn't return any useful data when I try accessing the data registers. I am using SPI to communicate with it and here is thelink to the datasheet. I have a commercial breakout board for the LSM9DS1 that is behaving the same but was working about 9 months ago. I think that I might have accidentally zapped or killed the poor thing in the months in between because I have another on my first revision that still functions (using the same code uploaded recently). I've been trying to figure out if I broke it and was wondering if any one else has experienced a similar issue. Thanks for your help in advance.Some additional deets for the interested few: I'm using a pic18F26k22 micro-controller for a small DC quad-copter (because I hate floating point and who really needs more than 8 bits anyway?). I had some minor success with the first iteration but needed to redesign because it had major technical issues (transistor power dissipation calculations are a thing). The control algorithm uses fixed point math for a PID controller and updates around 20 Hz (If I remember right).
LSM9DS1 - Pull-up resistor on INT? - Page 1
Forum section: electronics / beginners

author: Tantalum
author_rank: Regular Contributor
timestamp: March 24, 2019, 12:10:41 pm
content: HelloCan someone confirm that there is no need for a pull-up resistor on the 3 INT (INT1_A/G, INT2_A/G, INT_M) pin of the LSM9DS1 IMU?It's not indicated if it's open-drain or not.https://www.st.com/resource/en/datasheet/lsm9ds1.pdf
LT parts: why some parts have prefix LT, and other LTC? - Page 1
Forum section: electronics / beginners

author: exe
author_rank: Unknown
timestamp: May 28, 2020, 04:10:12 pm
content: Hi!I wonder why some parts are called LT<number>, and other parts are LTC<number>. What "C" stands for?

author: Kleinstein
author_rank: Super Contributor
timestamp: May 28, 2020, 05:02:03 pm
content: There are too many parts to have them all just numbered in one series. The LTC... parts are usually CMOS parts.

author: David Hess
author_rank: Super Contributor
timestamp: May 28, 2020, 07:26:26 pm
content: The LT prefix parts are bipolar and the LTC prefix parts are CMOS. I am not aware of any exceptions.

author: exe
author_rank: Unknown
timestamp: May 28, 2020, 07:42:21 pm
content: Ah, it is that simple. Thank you both!

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: May 28, 2020, 08:08:09 pm
content: Hi,The division between CMOS and Bipolar was blurred when BiCMOS processes were introduced.To the best of my knowledge LT never used the same number with LT and LTC prefixes.But generally 'C' for CMOS is true.Regards,Jay_Diddy_B
LT Spice default models - Page 1
Forum section: electronics / beginners

author: kc1980
author_rank: Regular Contributor
timestamp: May 11, 2010, 07:49:34 pm
content: Hi guys,I was messing around with a LT Spice default NMOS and found that it acted nothing like a typical n-channel enhancement mosfet. I gave it plenty of Vds and then I swept the gate voltage up to about 10V. Still, the drain current was in the microampere range. When I pick a specific nmos from the available list, everything works fine.Are most of the default models messed up?Thanks,Ken

author: mkissin
author_rank: Regular Contributor
timestamp: May 11, 2010, 09:44:56 pm
content: Close, but not quite....there is no default MOSFET model in LTspice (AFAIK). What would a "default" MOSFET even represent?You need to supply a .model statement for it to do anything. You can either do that through picking a specific device from the built-in lists, or supplying one yourself from a vendor website. You could even make one up yourself, but that's fairly difficult.If you're just after a really simple switch (which, if you're not supplying a model, I take it you are) then perhaps try a voltage controlled switch instead of a FET. You still need to supply a .model statement, but it's a very simple statement, with the threshold voltage and the on and off resistances.

author: kc1980
author_rank: Regular Contributor
timestamp: May 11, 2010, 11:42:15 pm
content: Cool! Thank you mkissin.
LT-Spice help, RL-circuit - Page 1
Forum section: electronics / beginners

author: somlioy
author_rank: Regular Contributor
timestamp: November 10, 2015, 12:46:22 pm
content: Hello.I'm trying to simulate this circuit, however I'm not getting the results I'm expecting. I've calculated the inductor-current by hand and by simulation in Matlab/simulink that the stationary current should end up at ~1.04A, but as you can see in the LTSpice simulation I'm only getting around ~0.95A. The inductor in LTSpice has a 1.5ohm series resistance. SW2 is open untill 0.5sec, so I'm currently only looking at the "charging" of the inductor-part in a simple RL-circuit.Is anyone able to see what I'm doing wrong in my simulation?For anyone interested the equations I'm working with:

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 10, 2015, 12:47:40 pm
content: LTSpice doesn't use ideal SPICE components, check the internal resistance of the switch and source.Tim

author: somlioy
author_rank: Regular Contributor
timestamp: November 10, 2015, 12:50:38 pm
content: Hmm, must be the switch then, because the Source is set to 0 at series resistance.Edit:And what dyu know, setting Ron to very low fixed the issue. Does LTSpice have any ideal switches?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 10, 2015, 01:24:38 pm
content: No, there's no such thing as an "ideal switch", as that would break SPICE. That is to say, it's a mathematical impossibility in real life, and a numerical nightmare in SPICE. (You could make one using an IF() statement, but don't expect the simulation to run very well.)The switch component more closely approximates an ideal MOSFET: the resistance varies smoothly from Ron to Roff over some range of input voltage, and therefore also hopefully over some range of time (continuity is paramount).(Truly real switches have all sorts of nasties, from arcing and contact bounce, to tunneling, surface interfaces, and contact resistance, so aren't really reasonable to even begin to model accurately.)Since you're adding resistance anyway, why not absorb the series resistance into the switch's Ron? The total resistance is simply the total resistance.Also, you can accurately and implicitly solve the equation you have provided: simply connect the voltage source (RS=0) to the resistor to the inductor, and set the inductor's initial current to 0. (You may have to check the Configuration panel to make sure LTSpice doesn't override your initial condition.)Tim
LT spice VCVS limit - Page 1
Forum section: electronics / beginners

author: gn_analog
author_rank: Newbie
timestamp: December 15, 2021, 12:53:47 pm
content: How to limit the output voltage of VCVS in ltspice?There is no options to give Vout maximum and minimum range.

author: Dave
author_rank: Super Contributor
timestamp: December 15, 2021, 01:17:53 pm
content: Create abehavioral sourceinstead and use math functionlimit(x,y,z)in the equation.

author: Ian.M
author_rank: Super Contributor
timestamp: December 15, 2021, 02:25:23 pm
content: Doesn't *anyone* read the LTspice help file?Quote from: E. Voltage Dependent Voltage Source
LT1054 Simple Question - Page 1
Forum section: electronics / beginners

author: lkm32
author_rank: Newbie
timestamp: May 31, 2014, 11:39:15 pm
content: Hello all,I've been working on a small project that needs a negative voltage rail and after trying out a whole lot of different options (virtual ground, two batteries, etc.) and decided on using a dedicated IC (LT1054IP in this case to give me a simple unregulated negative voltage). I am basing this on a circuit in the LT1054 datasheet.In simulation, the circuit works well but breadboarding it resulted in me only getting a positive 5 Volts at the output.Any advice as to what I might be doing wrong?

author: rxxbxyhxxb
author_rank: Contributor
timestamp: June 01, 2014, 06:13:17 am
content: Did you use the LT1054Lwhich is 3.5V~7V Absolute operating.

author: lkm32
author_rank: Newbie
timestamp: June 01, 2014, 04:17:48 pm
content: Quote from: rxxbxyhxxb on June 01, 2014, 06:13:17 amNo, I am using the LT1054IP from TI. Also, I am not even getting a negative voltage at the output.Sent from my Nexus 4 using Tapatalk

author: theatrus
author_rank: Frequent Contributor
timestamp: June 01, 2014, 04:42:41 pm
content: Did you build it as documented?What capacitors? Do you have a scope you can use to check if the unit is actually switching or attempting to?

author: lkm32
author_rank: Newbie
timestamp: June 01, 2014, 06:40:34 pm
content: Quote from: theatrus on June 01, 2014, 04:42:41 pm whelp I found out what the issue was. I feel stupid.I hooked up the cap + side to a scope and noticed that other than an initial poweron rise it would stay stable at around VCC.I then had the common sense to do continuity tests on the various jumpers and lo and behold the jumper from ground to the breadboard rail was broken.Replaced that and everything is fine now. I will get some tantalum capacitors tomorrow though to get less of a voltage drop at higher currents.Thanks for the patience and sorry for my stupid mistake.Sent from my Nexus 4 using Tapatalk

author: theatrus
author_rank: Frequent Contributor
timestamp: June 02, 2014, 12:51:32 am
content: It happens to the best of usI'd recommend MLCC ceramics for the most part, though tantalums are ok.

author: John Coloccia
author_rank: Super Contributor
timestamp: June 07, 2014, 01:22:43 pm
content: Depending what you're doing, you may want to protect the power input with a zener. I forget the spec off the top of my head, but if the absolute max rating is 12V, for example, I promise you that 12.0001V will blow it up. It's a common issue with these kinds of charge pumps.

author: lkm32
author_rank: Newbie
timestamp: June 07, 2014, 01:29:59 pm
content: Yup, abs max is 16V for unregulated so I have a 15.1V zener on the input.This may be out of scope, but is is possible to make an unregulated inverter using a MC34063 or the like? While not super necessary, it would be nice to have a greater input voltage range.Sent from my Lenovo B8000-F using Tapatalk
LT1108 in a dc step-up configuration - Page 1
Forum section: electronics / beginners

author: BeatleManiac
author_rank: Contributor
timestamp: January 04, 2016, 03:01:53 am
content: Hi!I'm what Dave would refer to as a "New Player" and I have a question concerning the LT1108 DC to DC converter. Here's the data sheet:http://www.linear.com/product/LT1108I'm using it in a Step-Up configuration and my question concerns the drawing labeled Figure-1 on pg 8. I understand how to get the desired output voltage using the resister divider connected to the FB pin, and how to choose the inductor using the provided formulas. However, there is no mention of how to choose the correct diode D1 and capacitor C1. I have various values of zener diodes so I'm assuming I'll be ok as long as I pick a reverse-bias voltage somewhat larger than V+. There is no mention of a procedure for choosing C1. I know I can just find one that works with trial and error but I'd like to understand the correct procedure.Thanks in advance for any help!Steve HurdFloyds Knobs, IN

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: January 04, 2016, 03:29:16 am
content: Hi Steve,Welcome to the Forum !!The LT1108 is older part.The Diode D1 should be a 1A Schottky. The capacitor C1 is typically a 100uF to 330uF low ESR electrolytic or polymer capacitor.There is an LTspice model for the LT1108.You might be better off using the LT3580.Link:http://www.linear.com/product/LT3580This part will switch at a higher switching frequency and be a smaller solution size.What is your input voltage?What is the output voltage?What is the maximum output current?Regards,Jay_Diddy_B

author: BeatleManiac
author_rank: Contributor
timestamp: January 04, 2016, 04:42:40 am
content: Hi Jay_Diddy_B!I'm wanting to use the lt1108 as a way to feed around 7V into my Arduino (no more than 400ma) so it can be assured of enough power. I'm using a 10A 5v DC source that will drive several programmable color-changing LEDS that will line the perimeter of my bass amp. I only want to siphon enough current off to power the arduino and supply +- 7v to my op amp that is in front of my bass signal and leave the rest of the current to drive the leds wich can take up to 30mA each. Op Amp output will then be dc offset so it doesn't dip lower than 0V and be fed into an input pin on the Arduino. Using a separate IC for the +7 to -7 conversion.I originally calculated and bought inductors for 5V into the Arduino when I saw that its input voltage dropped to about 4.5V after the LED strip was turned on. I only recently found that the Arduino prefers about 7V in to make sure it can run all the components at 5V. I was concerned about putting extra voltage into the board that the internal regulator would need to dissipate as heat since the ultimate home for this project will be in a guitar pedal.Hope this helps!Steve Hurd

author: BeatleManiac
author_rank: Contributor
timestamp: January 04, 2016, 08:31:33 pm
content: Where do you get the 100uF to 330uF value from? I'm trying to understand the theory behind the values as I go along.Thanks!Steve Hurd
LT1317 error in data sheet? Or, what am I doing wrong? - Page 1
Forum section: electronics / beginners

author: HooRide
author_rank: Regular Contributor
timestamp: September 24, 2014, 08:28:14 pm
content: Hi all, a project I'm working on requires 27V at 8mA to operate and plan to power it from two AA batteries. I've built a fully functioning prototype, PCB and all but the under voltage lockout is not working.I copied the lockout design verbatim from the Linear Technology data sheet but it does not work as expected. After some quick calculations, it looks like they made a mistake.If I understand it correctly, the comparator is on @ 200mV and off below 200mV.It works close to how they intended if the 340K resistor is swapped out for a 34K resistor (actually, 39K). Is there something wrong with their design or my implementation?Thanks!

author: HalfSpace
author_rank: Regular Contributor
timestamp: September 26, 2014, 10:54:24 pm
content: Hi HooRide,It’s a mistake by Linear Technology it should be 34K.If you calculate that the series 100K and 1M are in parallel with the 301K, we get (1/301K) + (1/100K+1M) = 1/total = 236K for the upper leg of the voltage divider when the LT1317 is in running mode.The voltage divider ratio is (236K/34K) + 1 = 7.94 so the low battery trigger level will be 0.2*7.94 = 1.58vWhen the LT1317 low battery level has been triggered the 1M resistor will be pulled to ground by the LBO pin placing it now across the 34K resistor, thus changing the low battery trigger level. The effect of the 1M in parallel with the 34K and the voltage drop across the NPN open collector of the LBO pin will be small so I will leave it at 34K.Now the voltage divider ratio will be (301K/34K) + 1 = 9.85 making the low battery trigger level 0.2*9.85 = 1.97v thus providing hysteresis to the circuit. This reduces the chance of oscillation or false triggering of the LT1317 if the battery voltage increases when it is placed in shutdown by the low battery circuit.Hope this helps.HalfSpace.

author: HooRide
author_rank: Regular Contributor
timestamp: September 27, 2014, 06:01:28 am
content: That helps immensely, thank you! Especially useful is the explanation of the hysteresis; very clever.I'll have to order a new sample because I can't trust this part to function 100% now that the LBI pin has seen 3x is absolute maximum.Thanks again!

author: stp715a
author_rank: Newbie
timestamp: November 16, 2018, 01:23:51 am
content: Hi.Did you get this to work? Thank you.
LT1764 adjustable current source - Page 1
Forum section: electronics / beginners

author: XgN
author_rank: Newbie
timestamp: January 19, 2022, 06:05:01 pm
content: Hi guys,Wanted to implement adjustable current source which is shown in LT1764 LDO datasheethttps://www.analog.com/media/en/technical-documentation/data-sheets/1764fb.pdfat page 16. The only change I did that placed OPA196 (higher min supply voltage and lower offset currents) instead of LT1366. But the output current is not adjusting only a ~50 miliamps at some point on R1 potentiometer. The output current is always at maximum according to the load/supply voltage. Is this schematic true? Seems interesting feedback capacitor C3 instead of a resistor. Or something else here I'm missing.

author: Capernicus
author_rank: Frequent Contributor
timestamp: January 19, 2022, 06:26:49 pm
content: Just use a good ol' potentiometre.

author: XgN
author_rank: Newbie
timestamp: January 19, 2022, 06:36:33 pm
content: The potentiometer in position R1 is brand new, 1k multiturn. As for CC source would like to push to the limits for transients and try to achieve a a few of ten microseconds stable constant current pulse at the output. The problem that this schematic is not working at all so far.

author: porter
author_rank: Regular Contributor
timestamp: January 19, 2022, 07:39:27 pm
content: I think the external op amp completes the feedback using the regulator via the sense/adj pin."SENSE (Pin 5/Pin 6): Sense. For fixed voltage versions ofthe LT1764 (LT1764-1.8/LT1764-2.5/LT1764-3.3), theSENSE pin is the input to the error amplifier"

author: KT88
author_rank: Frequent Contributor
timestamp: January 19, 2022, 08:09:57 pm
content: Just a stupid question: did you check the inverting and non-inverting inputs of the amplifier - I tend to exchange them accidentally from time to time just to annoy myself...

author: XgN
author_rank: Newbie
timestamp: January 20, 2022, 03:11:24 pm
content: Quote from: KT88 on January 19, 2022, 08:09:57 pmDouble-checked a few times..Quote from: porter on January 19, 2022, 07:39:27 pmThe error amplifier should be inside LDO and yes, this is the input pin to it. So far as I understand they decided to make another 1.2V reference and change "sensed" voltage according to the drop on the shunt. Nevertheless, in this schematic the non-inverting input of the opamp always gets power supply voltage (e.g. +5V) and not that 1.2V which was intended. Also the opamp should be in unity gain mode or something.

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 20, 2022, 08:33:43 pm
content: Just the LTSpice simulation. It's absolutely horrible. It starts at the max current (> 3 A) and takes a long time to settle, time which depends on R1 setting... and was not able to get lower than ~957 mA.Haven't investigated it much more than this.
LT1867 SPI to Arduino Nano - Page 1
Forum section: electronics / beginners

author: gilbenl
author_rank: Regular Contributor
timestamp: January 20, 2016, 11:55:22 pm
content: Does anyone have any sketches, which connect an arduino nano with an LT1867 they'd be willing to share? Just need something that I know is working to test some hardware configs. Admittedly, my coding is the opposite of strong.Would love you long time.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: January 21, 2016, 12:58:19 am
content: Hi,Linear has Linduino code or their website:http://www.linear.com/product/LTC1867The Linduino is LT version of the Arduino.Regards,Jay_Diddy_B

author: quantumvolt
author_rank: Frequent Contributor
timestamp: January 21, 2016, 03:48:01 am
content: I have used the Linduino library quite a bit - both for SPI and I2C. Below is a video using an ADC reading a DAC - 18 Bit DAC (LTC2756) to 24 Bit ADC (LTC2400) Loop Back.The DAC is connected to PC via Linduino to USB. The DAC outputs the voltage that is chosen in QuikEval software.The DAC output voltage is measured by the ADC. The ADC is connected to PC via an ebay Arduino Uno clone w/ the Linduino-clone shield to another USB port.A GUI written in C++ in Processing receives the ADC data and outputs them to screen.If you read this threadhttps://www.eevblog.com/forum/projects/linduino-smart-isolated-arduino-compatible-board-for-daq-demo-boards-etc/msg301469/#msg301469you will also find a video reading an ADC directly via Arduino to the Arduino IDE serial window.Most importantly you will find useful information and contact email to LTC's Leo (the man who works with Linduino). See 'Going generic' herehttp://www.linear.com/solutions/Linduino.
LT1936 Step Down Regulator Voltage out Calculation - Page 1
Forum section: electronics / beginners

author: koba30
author_rank: Contributor
timestamp: September 17, 2018, 12:16:50 am
content: Hi,I made the calculation for the Output voltage of the LT1936 ic, but the voltage obtained is different of the voltage on the real circuit output.This is the typical application, when I use the equation on this works fine the result is 3,288.This is the equation for calculate R1, I solve for Vout.Block diagram, the same configuration of the real circuit.This is the real circuit, R1 is 33kohm, R2 is 27,05kohm the parallel of 150kohm and 33kohm resistor.The Output Voltage that I measured is 5,407v but the calculated with the ecuation is 2,66v.The Output Voltage required must be 5v.Can someone please help me to understand what is happening.Thanks in advance

author: Zero999
author_rank: Super Contributor
timestamp: September 17, 2018, 10:24:18 am
content: That sounds right.VOUT= VREF*(1+R1/R2)VREF= 1.2VR1 = 33kR2 = 27.05kVOUT= 1.2*(1+33/27.05) = 2.66VThe data sheet recommends R2 < 20k to minimise the effect of bias currents, but even with the worst case bias current of 300nA, you'd only get 8.1mV of error with R2 = 27k05.Are you sure the resistors are the values you believe they are? Try measuring them.

author: Ian.M
author_rank: Super Contributor
timestamp: September 17, 2018, 11:30:43 am
content: Reading the markings on the resistors,, there's a 10K off on the left, then just above the chip, two 33K with a 15K in between them. There is no 150K visible.If R1 is the top 33K and R2 is the bottm two: 15K||33K, that would give a nominal output voltage of 5.04V

author: koba30
author_rank: Contributor
timestamp: September 18, 2018, 02:07:12 am
content: Hi,I made a mistake, thank you very much Ian.M and Hero999 for your help, the correct value for the resistor is 15KI made calculations for many hours
LT3066EMSE-3.3 - Page 1
Forum section: electronics / beginners

author: zhivko
author_rank: Newbie
timestamp: July 07, 2018, 04:54:52 pm
content: I try to use fixed 3.3V variant of LT3066 to get 3.3V on output from 45V input. I use: LT3066EMSE-3.3. Problem is that I get Vin to Vout.My schematics is as follows (attachment).Datasheet is here:http://www.analog.com/media/en/technical-documentation/data-sheets/3066fa.pdfCan somebody tell what is wrong with current schematics that I get 12V on OUT_1 and OUT_2 pins if I connect 12 V to IN_1 and IN_2 pins?Thank you and regards,Zhivko

author: pyroesp
author_rank: Regular Contributor
timestamp: July 07, 2018, 05:19:09 pm
content: You need to connect the sense wire to the output.Also, best use a resistor on PWRGD. There's a MOSFET to GND, see the system block diagram in the datasheet.

author: zhivko
author_rank: Newbie
timestamp: July 08, 2018, 07:01:56 pm
content: Thank you very much - you are correct.This is schematics (part of datasheet):

author: tsman
author_rank: Frequent Contributor
timestamp: July 08, 2018, 07:56:20 pm
content: What sort of current requirements do you have for the 3.3V output? 48V in and 3.3V out with this linear regulator will mean it gets incredibly hot even with fairly low current output. Look at page 20 of the datasheet and put in your numbers to work out what temperature rise to expect and what your maximum current output will be before it hits the maximum rated temperature.

author: zhivko
author_rank: Newbie
timestamp: July 09, 2018, 07:15:26 am
content: Max current that needs to be provided is 300mA, but this is when ESP32 chip is initializing or sending data. Otherwise most of the time is below 100mA.Yesterday I made required changes (connected sense to Vout) and didn't finger test if chip gets hot. But will do that and report back.regards and thank you very much for your comment!.

author: zhivko
author_rank: Newbie
timestamp: July 09, 2018, 07:17:54 am
content: If I don't use PWRGD - is it OK to let it float? I guess it is OUTPUT and used by some power monitoring chip that supervises this power chip?
LT3080 Higher Current Output: How does it work? - Page 1
Forum section: electronics / beginners

author: Stephen Hill
author_rank: Regular Contributor
timestamp: May 28, 2012, 12:33:41 pm
content: So I saw this circuit schematic on the LT3080 datasheet and I would please like help understanding how the MJ4502 PNP, 50? Resistor and the LT3080 work together to control the output voltage.My current guess (from playing with the circuit in LTSpice) is that the 50? Resistor create a small voltage drop between Vctrl and Vin which creates a voltage potential between the emitter and base. This then allows the current drawn by the LT3080 to adjust the output voltage of the PNP by pulling current out of the base.Am I correct or completely wrong?Many ThanksStephen

author: Fox
author_rank: Regular Contributor
timestamp: May 28, 2012, 01:15:17 pm
content: Hi Stephen,you got it correct.This arrangement is called complementary Darlington or Sziklai pair. The advantage is that the base turn-on voltage is only 0.6V instead of 1.2V with a classical Darlingtonpair.BTW. Sometimes it helps to simply redraw the circuit in another arrangement of the components (at least it helps me) to understand what's going on.

author: Stephen Hill
author_rank: Regular Contributor
timestamp: May 28, 2012, 01:46:17 pm
content: Hi Fox,Thank youI didn't think to redraw and thus simplify the circuit - something to remember for next time.Many ThanksStephen

author: onlooker
author_rank: Frequent Contributor
timestamp: May 28, 2012, 02:37:01 pm
content: Well, Darlington pair does not explain why the 50 Ohms is there;"Reduced turn on voltage" is not the key either since to have the MJ4502 do anything useful, one needs to have (VIN-VOUT) > 1.2 plus V at least at larger load level; then, min (VIN-VOUT) > 1.2V plus V needs to be fixed from design for all load levels. In other words, "reduced turn on voltage" did not help much.The OP's statement "the 50? Resistor create a small voltage drop between Vctrl and Vin which creates a voltage potential between the emitter and base" is also a wrong way to approach the answer. MJ4502 does not need the resistor to bias it; LT3080 is the one bias MJ4502; In fact, the 50 ohms is to remove the bias effect of Lt3080 for small load level. It is not required to have voltage drop btw Vin and Vctrl either.The main effect of the the 50Ohms is to reduce the the required minimum current load of the design to that of LT3080(0.5mA) by effectively shutting off MJ4502 at small current load. If w/o this resistor, the 0.5mA required for LT3080 to work properly will go through EB of MJ4502, assuming a gain of 40, the minimum current load of the design will be 40x0.5=20 mA now. In addition, the design has to accomendate variations in MJ4502's gain. To have easier understanding, a dummy resistor that provade the min current load passage can be draw btw Vout and ground.
lt3080: how did they achieve 350mV dropout? - Page 1
Forum section: electronics / beginners

author: exe
author_rank: Unknown
timestamp: January 30, 2016, 11:47:36 am
content: Hi!I'm curious how can lt3080 have just ~350mV dropout under full load(1.1A). Any ideas? The datasheet says it's a npn-regulator with a separate Vcontrol pin that consumes up to 30mA (needs to be pulled +1.2V above Vin or dropout will be much bigger). According to the datasheet, it supplies internal opamp that drives BJT. So... Does this mean they use some good NPN transistor with very low Vce(sat)?A 30mA consumption for the opamp and 1.1A max output gives me ~37 hFE (assuming all this current drives the pass element). I tried to find a similar part in digikey, but there are just a few parts with such a low saturation dropout.... Did I miss something? Or may be I'm wrong on how lt3080 works inside?

author: MagicSmoker
author_rank: Super Contributor
timestamp: January 30, 2016, 12:42:58 pm
content: The key is in this blurb from the datasheet:QuoteVcontrol is the supply terminal for the error amplifier and reference and if it is at least ~0.6V higher than the voltage at the pass transistor collector ("In") then the minimum dropout at Vout is Vce.

author: exe
author_rank: Unknown
timestamp: January 30, 2016, 08:34:57 pm
content: Quote from: MagicSmoker on January 30, 2016, 12:42:58 pmThank you, that what I was looking for.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 31, 2016, 07:56:11 pm
content: Vce(sat) goes down to < 0.1V for sufficiently large transistors. It's likely the transistor takes up more area than, say, the main output device in an LM317, for this reason.Tim
LT3080 - PWM/DAC+Opamps VS digipot - Page 1
Forum section: electronics / beginners

author: Tooms
author_rank: Unknown
timestamp: March 23, 2012, 05:34:41 pm
content: HiI am an beginner in electronics and i playing with the LT3080 and can see the SET pin only has around 10 uA.So why are you using PWM+opapms or DAC+opapms to drive the SET pin, will it not just be better to use some digipots to control it ?Some thing like 4 cheap 8bit digipots in serias and that will give you 24bit (4*8bit) controlThanksThomas

author: sacherjj
author_rank: Frequent Contributor
timestamp: March 23, 2012, 05:54:42 pm
content: Quote from: Tooms on March 23, 2012, 05:34:41 pmIt isn't quite that simple. The "wiper" resistance of digipots is factor that will compound with more in series. This will give you an overall offset of something other than zero.DAC wins in resolution and accuracy. You would have to add up all the error in a digipot, to get your worse case error. This would involve a shift of values, due to missing the zero point, plus worse case error of 4x the single error of an 8-bit pot.

author: Bored@Work
author_rank: Super Contributor
timestamp: March 23, 2012, 06:25:38 pm
content: Digital pots are the band aids of inexperienced designers. In most cases I have seen them used it was a bodged job.You can't get digital pots with really high resolution. 1024 is the most many manufacturers offer, if at all. 256 is common.Digital pots have horrible tolerances, think 20%.Digital pots can't be adjusted down to zero.Digital pot wiper resistance depends somewhat on power supply voltage.

author: Tooms
author_rank: Unknown
timestamp: March 24, 2012, 10:55:19 am
content: ahh yes offcource the tolerances will get very bad when stacking up the digipots.I was just thinking that it was cheaper and easyer to get an very high bit sample with the stacking of the digipots then it was to get the PWM/DAC with high bit samplesThanksThomas

author: T4P
author_rank: Super Contributor
timestamp: March 24, 2012, 01:05:29 pm
content: A DAC is easier to useNo nasty tolerance differences and it's not easy to parallel 20% tolerance things , it can end up quite inaccurate
LT3083 portable supply - Page 1
Forum section: electronics / beginners

author: pjwl
author_rank: Newbie
timestamp: December 12, 2019, 03:13:01 pm
content: Hello,I'm trying to make my own uSupply with the LT3083, I would like to have 0..5V output with 0..2A.After studying the forum: uSupply - LM350T instead of LT3080 I cam with a similar idea which I did made up in LTSpiceI need to add 1mA load because the LT3083 requires that, but when simulating every seems to work okay.I was wondering if some has tips and maybe some suggestion for some cheaper opamps.ThanksPjwl

author: David Hess
author_rank: Super Contributor
timestamp: December 12, 2019, 08:56:09 pm
content: The LT6220 is not doing anything useful. Removing it will improve performance of the current control loop and make frequency compensation easier.The AD8031 is much faster than required for this application. If a single supply precision part is required, then the LT1013 is both inexpensive and fast enough given the external compensation shown in the schematic.If you used the AD8031 for higher slew rate to lower switching time between current and voltage control, then the external frequency compensation is defeating that reason. A slightly different configuration which clamps the output of the inactive error amplifier may be necessary if you want the fastest switching between current and voltage control.
LT3461A Through-hole equivalent? - Page 1
Forum section: electronics / beginners

author: Siva-Na-Gig
author_rank: Newbie
timestamp: September 06, 2019, 09:50:02 pm
content: I'm working on a school project converting an SMT design to Through-Hole to make it a bit easier to work on with what we have available. Finding an exact Through-hole equivalent for an LT3461A is eluding me, can anyone give me any suggestions or advice? I'm not against redesigning the circuit somewhat to make something else work, though it would be pretty advanced for me to attempt that.

author: orbanp
author_rank: Regular Contributor
timestamp: September 08, 2019, 11:24:26 am
content: Chances are you need to redesign the circuit.Go to a distributor web-site (Digikey, Mouser, e.t.c.), enter the search engine for a through hole boost type controller IC, and you will have a number of choices.Download the data sheet and go from there.Good luck, Peter

author: Ian.M
author_rank: Super Contributor
timestamp: September 08, 2019, 02:17:05 pm
content: Generally, you wont be able to find one. High switching frequency PSU chips strongly tend to be SMD only due to the need to shrink the loop area as much as possible to minimise radiated EMI and to avoid instability. That also means slapping a LT3461A on a generic TSOT23-6 to DIL breakout board isn't an option.You can probably find something old fairly easily that switches in the 50KHz to 200KHz range in DIP or TO220-5 packages, but it will need *MUCH* larger and more expensive inductor and capacitors.IMHO your best course of action would be to keep the section around the LT3461A surface mount. There's nothing there that's too tricky to hand solder, but if for example, it must be assembled by students, consider making it a small daughterboard following the recommended datasheet layout that can be preassembled by staff.
LT4230 3 Phase rectifier - Page 1
Forum section: electronics / beginners

author: jram
author_rank: Contributor
timestamp: May 16, 2018, 04:31:26 pm
content: Hi all,I've had a good read of the other threads using this chip and it seems like a decent choice for the job of reviews recifying3 phases from a wind turbine with a max outputcurrent of 50A. I'd be grateful to know if anyone has already implemented this type of rectifier.I've looked at the reference design from linear and Initial thoughts are that I should choose mosfets for an average current of about 20A per phase .Maximum voltage may be an issue though as a wind turbine feeding into too high an impedance might push the voltage too high and I'll be looking at clamping that to a reasonable maximum.It's early days so any experiences would be apprecited.ThanksJ
LT4320 PCB - bridge drop in replacement - Page 1
Forum section: electronics / beginners

author: seavan
author_rank: Contributor
timestamp: May 12, 2025, 01:32:04 am
content: I used to make pcbs with nail polish many years ago. This is my first attempt at using "proper" tools. I could not find a good open source pcb for a small lt4320 pcb, so I decided to take an opportunity to learn KiCad and make a rectifier bridge drop-in replacement. I will appreciate your feedback.https://github.com/mstolpner/lt4320-bridge-drop-in/tree/main
LTC 3588 - Page 1
Forum section: electronics / beginners

author: kristen Ha
author_rank: Newbie
timestamp: November 02, 2013, 06:41:58 am
content: Does anyone knows on LTC 3588?Is the IC needs a voltage of 2.7 V in the storage capacitor before the in-built regulators can function?

author: Alana
author_rank: Frequent Contributor
timestamp: November 02, 2013, 08:36:04 am
content: Show us your scematic and if possible pictures of prototype device.

author: kristen Ha
author_rank: Newbie
timestamp: November 02, 2013, 02:29:10 pm
content: I am following the schematic of the evaluation board of 3588https://www.sparkfun.com/datasheets/BreakoutBoards/energy_harvester-v12.pdf