hybridfree/eevblog-posts huggingface dataset:
RC LPF Filter - Page 1
Forum section: electronics / beginners

author: timj
author_rank: Newbie
timestamp: March 02, 2019, 03:14:45 pm
content: Hello, I'm a beginner in electronics, sorry if what I'm asking is basic. I have a task for one of my assignments which I'm unsure about. It is about RC LPF filters. I am asked to modify a circuit so the cut-off frequency is doubled. How would I go about doing so? Would I simply reduce the resistor or capacitor value for the formula: F(cutoff)= 1/2piRC. Also how would I show this practically? My lecturer says to keep the amplitude of the input constant but I'm not sure what he means by that. The circuit consists of just a signal generator, supplying a resistor of 1k and capacitor of 100n and a Vout measurement between the resistor and capacitor. Any help would be great. I have also attached an image.

author: bson
author_rank: Unknown
timestamp: March 04, 2019, 02:35:25 am
content: It doesn't matter which you change; the cutoff frequency follows their product, R*C. Reducing either will increase the cutoff frequency since it's reciprocal. The choice of values is mainly practical; smaller values for R increase current consumption and power dissipation, large values for R increase noise, and larger capacitors are physically bigger and cost more. Since the current values are presumably well-chosen, you could reduce both enough to double the cutoff frequency. Of you could reduce the capacitor alone; usually smaller capacitors are a win, at least down to 100pF or so.

author: todorp
author_rank: Regular Contributor
timestamp: March 04, 2019, 08:35:10 am
content: To keep the loading of the source similar only the cap C should be reduced (without touching the R).

author: timj
author_rank: Newbie
timestamp: March 04, 2019, 09:11:06 am
content: So if the audio generator has an output impedance of 600ohm, does that mean I'll need to include that in my calculation for R1?

author: timj
author_rank: Newbie
timestamp: March 04, 2019, 09:14:03 am
content: Also I kept V_in the same amplitude (1v), but when I change frequencies from 100Hz to 1kHz the amplitude drops and is not constant. Shouldn't it be the same, as those frequencies are before the roll off?

author: MrAl
author_rank: Super Contributor
timestamp: March 04, 2019, 01:52:43 pm
content: Hi,The amplitude of the output of the RC low pass filter is:Vout/Vin=1/sqrt(w^2*C^2*R^2+1)and the -3db cutoff point is reached when:1/sqrt(w^2*C^2*R^2+1)=1/sqrt(2)Solving this for w^2 we get:w^2=1/(R^2*C^2)and this leads to one non negative solution:w=1/(R*C)and of course w=2*pi*f with 'f' the cut off frequency in Hertz.So we have:2*pi*f=1/(R*C)or:f=1/(2*pi*R*C)Now since R and C are both in the denominator, that means making R or C smaller by a factor 'a' makes the frequency 'f' go up by the same factor 'a'.This means to raise the cut off frequency you have to make either R or C (or both) smaller.So if we make C smaller by 2 times, the cut off frequency will go up by 2 times.
RC Network - Page 1
Forum section: electronics / beginners

author: veedub565
author_rank: Frequent Contributor
timestamp: September 03, 2019, 04:16:55 pm
content: Hi, quick question. Is it important to have an electrolytic capacitor in a simple RC network (consisting of one resistor and one capacitor in series with a voltage source)Would it work with a non polarised capacitor?

author: Zero999
author_rank: Super Contributor
timestamp: September 03, 2019, 04:20:49 pm
content: Yes, a polarised capacitor can be easily replaced with a non-polarised capacitor.

author: veedub565
author_rank: Frequent Contributor
timestamp: September 03, 2019, 04:29:41 pm
content: Thanks
rc plane locator - Page 1
Forum section: electronics / beginners

author: John t
author_rank: Newbie
timestamp: December 02, 2014, 12:40:52 am
content: Hello I'm trying to build a circuit for finding a downed rc airplane around a 555 chip that when turn on just before taking off would admit a chirp orbuzzer say 2 to 4 times then be silent for 30 second give or take a few then cycle again I've tryed numerous configurations with no resultsHelp please...

author: IconicPCB
author_rank: Super Contributor
timestamp: December 02, 2014, 12:57:05 am
content: Try the followinghttps://www.google.com/search?q=fox+hunt&ie=UTF-8&sa=Search&channel=fe&client=browser-ubuntu&hl=en&gws_rd=ssl#channel=fe&hl=en&q=rf+fox+huntingShould give You some insight into the problem

author: Richard Crowley
author_rank: Super Contributor
timestamp: December 02, 2014, 01:13:35 am
content: Yes, the traditional way was to use a "beacon" which you could triangulate on with direcitonal antennas (aka. "fox-hunting").The 21st century way is to use a GPS and a transmitter which will broadcast the exact location so no searching is necessary.There is a whole sub-culture of amateur radio ("ham" radio) called APRS (Amateur Packet Radio System or Automatic Packet Reporting System)And a subset of APRS which uses very small GPS receivers and APRS transmitters to allow you to track almost anything on the planet.Depends on which is more important: the activity of searching and finding the lost craft, or simply locating it for rescue.APRS overview:http://en.wikipedia.org/wiki/Automatic_Packet_Reporting_SystemAPRS website:http://www.aprs.org/Typical APRS tracking beacon:http://www.bigredbee.com/(one of many)Typical online APRS tracking map:http://www.openaprs.net/(one of many)OTOH, to answer your original question, it is common to use a DUAL 555 where the first one implements the timeout (30 seconds or whatever), and the second one actually generates the locating tone. You would want to tune it to the resonant frequency of a small piezoelectric transducer for maximum audible output at minimal payload weight/mass.

author: Jeroen3
author_rank: Super Contributor
timestamp: December 02, 2014, 07:23:21 am
content: You can already buy those beepers. They will start beeping when there is no change in servo signal for an amount of time.For less than the time you'd be spending.We call them corn-beepers. Since when you lose the rc plane in a corn field you'll have a hard time finding it again.

author: kaindub
author_rank: Regular Contributor
timestamp: December 03, 2014, 11:15:54 am
content: I contributed such a project to elektor magazine. It was published in April 2013.I used a picaxe to generate the signals.Robert
rc radio repair - Page 1
Forum section: electronics / beginners

author: centi4554
author_rank: Newbie
timestamp: March 17, 2022, 11:47:29 pm
content: Hi, this is my first post here sorry for english mistakes ,im trying to repair an old german rc radio VARIOPROP12S, i ve posted a shematics and a picture. the radio stops working after a stupid mistake by me , i ve pluged 12v power supply in it upside down , it still turns on but can not send controls to the receiver.i ve already changed fried transistor T104 , but stil wont work.now im suspecting the 74164 ic cose it s the one who take signals from pots to the transistors.my question is it possible to bypass the 74164 ic , can connect directely from pots to transistors , or replacing it with transistors .. ?why i want to bypass it because this chip gdf1100 is not longer available for sale it s old from seventies.any ideas ?

author: BrokenYugo
author_rank: Super Contributor
timestamp: March 18, 2022, 01:03:04 am
content: 74164 is obsolete, but the 74LS164 is still made and should be close enough.
RC relay delay circuit question - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: September 18, 2012, 11:29:34 am
content: 24V DC relay with coil resistance of 445 Ohms. Coil energising circuit is 110V AC via a 6A10 diode, a 1K Ohm ceramic wire wound 12 watt resistor, and 2200 uF electrolytic. Coil delay is just over 1 second. Measured voltage across relay coil is about 21 volts DC. All works well except the 12 Watt ceramic wire wound runs a bit hot, I may use 3 off 3k Ohm in parallel. Problem is relay is slow to disengage when power to the coil is removed, due to retained voltage in the electrolytic. It's meant as a safety shut off relay (interlock) for a power supply. Is there a way to make it release instantly, or near as damn it instantly? Thanks.

author: David_AVD
author_rank: Super Contributor
timestamp: September 18, 2012, 12:11:10 pm
content: Perhaps a second relay run from the raw source that has it's N/O contact in series with the first relay's coil (or the output contact)?

author: vk6zgo
author_rank: Super Contributor
timestamp: September 19, 2012, 03:19:41 am
content: If you are using it as an interlock relay,why do you have an operate time delay?Is it also being used for the slow start function you asked about before,or is it just that you need the electro to make the DC relay work on the halfwave rectified pulsating DC?If it is supposed to cut off the HT to a valve Amplifier,you could drive it off a bridge rectifier from the filaments instead of your current setup,& filter the supply properly.The interlock switch could then just break a clean DC feed to your relay,& you could ditch the Electrolytic.If you need the operate delay,you may be able to put a diode in line with the electro,where it can charge to give the delay,but not discharge through the relay coil,so the relay will drop straight out.As the cap will have to discharge eventually,you will need to have a higher value resistor across the coil all the time.I'm not sure this will work with the pulsating nature of the halfwave rectified AC.

author: Simon
author_rank: Unknown
timestamp: September 19, 2012, 09:54:32 am
content: You need to explain your application more. Do you need the delay ? or are you using the capacitor to smooth out the DC ? if so remove it, you can manage without. Preferably use a full wave rectifier, but I would think you can get away with reducing to 48V (or a bit less) on a single diode (50% duty) which will also reduce the heat in your resistor.At present you need a 2.25W resistor
RC TIMING AND FREQUENCY TO RISE TIME CALCULATOR - Page 1
Forum section: electronics / beginners

author: kumar
author_rank: Contributor
timestamp: June 18, 2014, 04:08:36 am
content: I am looking for two calculators ( which can be downloaded )1) RC timing calculator2) Frequency to rise time calculatorCan anyone please help me?

author: Dave
author_rank: Super Contributor
timestamp: June 18, 2014, 04:14:56 am
content: Grab a calculator and calculate that yourself.I guarantee it's faster than loading up a calculator app on your phone/tablet and typing in values.
RC toy car - Page 1
Forum section: electronics / beginners

author: slashguitar
author_rank: Contributor
timestamp: January 06, 2012, 02:06:42 pm
content: Hello,I just took apart another toy car ... and it's the same TX-2B/RX-2B circuit found in most chinese craphttp://pro-radio.ru/user/uploads/126799.pdfone thing that keeps bugging me is the inductor on the motor wires. What's it's purpose? Is it part of a filter or snubber?thanx

author: 8086
author_rank: Super Contributor
timestamp: January 06, 2012, 02:33:33 pm
content: I would assume EMI suppression?

author: firewalker
author_rank: Super Contributor
timestamp: January 06, 2012, 02:37:06 pm
content: My guess is that it is a filter preventing interference, from the motor's brushes, affecting the circuit.Alexander.

author: SeanB
author_rank: Super Contributor
timestamp: December 17, 2012, 11:11:16 am
content: The toroid along with the 100n ceramic on the motor terminals form a common mode choke, so that the RF noise from the brushes does not interfere much with the receiver on board. If you remove them you will find range much reduced from what it was, and the car will be prone to locking up at full speed at times.
RC Transmitter / Receiver Question - Page 1
Forum section: electronics / beginners

author: Longhair
author_rank: Regular Contributor
timestamp: January 06, 2011, 01:34:17 pm
content: I want to do some basic things like turn on/off LEDs from a spare channel that is not in use. What I have done was just take a part a servo, removed the motor and soldered a couple of wires on the board for a basic switch. Simple enough...One of the reasons for myself to get into electronics is to be able to do more than turn on/off LEDs - say have high/low/off LEDs. I could just add some different value resistors and adjust the trim settings on the radio. Actually I have and it has been a hit & miss but still in the end, the results were there, just not perfect. That is fine if there is only 1 set of lights and 1 spare channel, but the problem lies when there is a need for 2 independently controlled lights (one low, one off / both low / one low, one high / etc.) and there is only 1 spare channel.What area should I be learning or what is it generally called? I am just talking about from the receiver to the device, not from the radio to the receiver.

author: DaveW
author_rank: Frequent Contributor
timestamp: January 06, 2011, 01:50:46 pm
content: The easiest way to do this, and the most flexible if you want to be able to modify/expand later would to use a microcontroller-you can feed an R/C signal in, measure the length and then do almost anything depending on the signal. Switching can be done using the standard I/O, you can dim a LED with 256 levels of control using PWM, which can be expanded into motor control etc; almost anything you'd want to do for R/C.Used to recommend the PICAXE chips for learning, but the arduino development systems are fantastic and loads of support & code around. In your case, the pulsein command would give you the length of the pulse and is already written for you. Something like the lilypad board would probably be powerful enough for most of these applications and is nice and lighthttp://arduino.cc/en/Reference/PulseInhttp://arduino.cc/en/Main/Hardware

author: Jimmy
author_rank: Regular Contributor
timestamp: January 07, 2011, 06:27:55 am
content: I have done this with rgb led using 1 wire serial rx to another micro it is easy I had 1 transmitter and 8 recivershttp://www.sparkfun.com/datasheets/RF/KLP_Walkthrough.pdf
R/C - Page 1
Forum section: electronics / beginners

author: mtc2629
author_rank: Contributor
timestamp: October 07, 2013, 01:25:30 am
content: what is the best way to control a home made car by any remote with arduino

author: Maximus64
author_rank: Newbie
timestamp: October 07, 2013, 02:00:37 am
content: Using IR sensor?

author: peter.mitchell
author_rank: Super Contributor
timestamp: October 07, 2013, 03:55:11 am
content: What do you mean "by any remote"? You see, if you're referring to television and other consumer electronics equipment remote controls, they often are different between models, manufacturers and regions, so there is no one way to use "any" remote.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: October 08, 2013, 09:00:18 pm
content: Dave did a great video showing how to decode the output from an IR remote control using an Arduino and then play it back. It would make a good place to start. I was really quite stoked up watching it.

author: Sigmoid
author_rank: Frequent Contributor
timestamp: October 08, 2013, 09:23:21 pm
content: Well since the topic title is R/C, and we're talking about model cars, I'd assume the op wanted info on radio control.Using a TV remote to control a toy car sounds tedious, unintuitive, and the absolute least amount of fun I can imagine.However, in such broad terms, the "best way" would be googling "R/C with arduino", and reading the hits that make sense.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: October 08, 2013, 09:35:25 pm
content: If the OP had two Arduinos or bare chips to play with, he could have a look at the 433Mhz RF transmitter and receiver kits for Arduino projects on eBay. They are ridiculously cheap.I bought a couple of sets to play with and it was very easy to get one device sending text messages to another.
RCA jacks for panel mounting, ground connection - Page 1
Forum section: electronics / beginners

author: robert555
author_rank: Newbie
timestamp: April 04, 2014, 11:45:04 am
content: Hello!I bought a few rca jacks on ebay. And i don't know how to connect the ground to the contacts?

author: David_AVD
author_rank: Super Contributor
timestamp: April 04, 2014, 11:48:56 am
content: Simply solder to one of the ground lugs? Any reasonable iron should do that fine with the right technique.

author: robert555
author_rank: Newbie
timestamp: April 04, 2014, 12:08:35 pm
content: Jo thought about it I too, but it feels a bit dodgy. But may well do so if there is any better way to solve it.

author: Holograph
author_rank: Regular Contributor
timestamp: April 04, 2014, 02:35:53 pm
content: Quote from: robert555 on April 04, 2014, 12:08:35 pmIf you want to be sure you get an excellent connection, loop the wire around and solder it to both points (just make sure it won't touch the center lug). If you have a Dremel, you can make it even less likely to fail if you put little notches at the bottom of the ground lugs, and wrap the wire all the way around, in the notches, and then solder it. The notches aren't necessary, but they would help keep the ground wire from being pulled away from the jack. But there shouldn't be much pressure applied on that wire, really, anyway.You could potentially also source or make a grounding ring with a solder lug that has a hole, if you really want. Again, I wouldn't say it's necessary. And it would add a little more resistance that way. I don't prefer grounding rings.Overall, you need to be more careful when soldering this than if you had a grounding ring because there's a lot more metal in this and you'll need to be sure to get it hot enough.

author: linux-works
author_rank: Super Contributor
timestamp: April 04, 2014, 03:32:30 pm
content: solder to one of the legs. no big deal. nothing wrong with that. its not rf, its just audio.but - be sure not to melt the insulation if you use too much heat for too long!

author: G7PSK
author_rank: Super Contributor
timestamp: April 04, 2014, 05:30:13 pm
content: Will a spade connector fit the lugs.

author: Monkeh
author_rank: Super Contributor
timestamp: April 04, 2014, 05:32:59 pm
content: Quote from: G7PSK on April 04, 2014, 05:30:13 pm.. fairly clearly, no.
RCA RF transistor datasheet  - Page 1
Forum section: electronics / beginners

author: LaserTazerPhaser
author_rank: Regular Contributor
timestamp: June 06, 2019, 10:47:47 pm
content: Does anybody have a datasheet for this part? Box says 249688 refer to SPS 3409

author: joeqsmith
author_rank: Super Contributor
timestamp: June 07, 2019, 12:32:08 am
content: Maybe an MRF231? Are you sure it was an RCA part?https://www.rfparts.com/mrf231.html

author: floobydust
author_rank: Super Contributor
timestamp: June 07, 2019, 03:16:26 am
content: It's a Motorola part, 798-3 likely a house number. There was 798-1, 798-2 in the mid 1980's.You'd have narrow down the year and look at Motorola's offerings to guess the original part number.Transistor Devices Inc. SPS3409 Nexrad radar power supply?

author: David Hess
author_rank: Super Contributor
timestamp: June 07, 2019, 03:37:53 am
content: The SPS marking makes me think it is a Motorola part.
RCA Tube Identification - Page 1
Forum section: electronics / beginners

author: Johnny10
author_rank: Frequent Contributor
timestamp: June 05, 2017, 02:30:54 pm
content: I should probably be better at determining tube type by construction but wondering if anyone can tell me what RCA tube this is.All lettering has been cleaned off.It has an 8 pin octal tube base.RCA 66-48 on Base.

author: Paul Price
author_rank: Super Contributor
timestamp: June 05, 2017, 02:33:43 pm
content: This looks a full wave rectifier, something like a type 5U4, 5Y3.I can clearly see there is no grid, two plates and a filament, rather than a cathode.To verify, find the two heater(filament) pins, they will show a low-resistance and connect to two pins only and if they match the pinout of the 5U4 or 5Y3, my guess is correct.Most other non-rectifier tubes instead usually use pins 2 and 7 for heater connections.

author: Johnny10
author_rank: Frequent Contributor
timestamp: June 05, 2017, 02:48:00 pm
content: 6AS7 ?

author: TimFox
author_rank: Super Contributor
timestamp: June 05, 2017, 02:52:01 pm
content: The tube number should be on the glass envelope, either on the side or the top. The lettering tends to fade with time and can be hard to read. An old trick, which needs to be applied carefully, is to apply skin oil from your finger to the letters and look carefully, rotating with respect to the light.Note that other rectifier tubes had different filament connections. The 5Y3 and 5U4 types have the filament (directly heated cathode) between pins 2 and 8 (tube pins are numbered clockwise from the bottom), but the 5X4 uses 7 and 8. Other rectifiers, such as the 5AR4, have the heater between 2 and 8, with an indirectly-heated cathode at pin 8.When you identify the heater/filament connections as suggested above, note that the "cold" resistance measured by your ohmmeter is much lower than the "hot" resistance corresponding to 5V/2A (5Y3) or 5V/3A (5U4) in operation.The best reference for tube data online ishttp://frank.pocnet.net/

author: schmitt trigger
author_rank: Super Contributor
timestamp: June 05, 2017, 04:37:53 pm
content: I agree that it looks like a rectifier diode.Once that you find the heater connections, apply 5 volts DC and measure the current.Now go to tube specs of a few of the directly heated diodes, and compare your current readings with those of the spec sheet.With that, at least you verify the tube type.

author: Johnny10
author_rank: Frequent Contributor
timestamp: June 05, 2017, 04:57:11 pm
content: 6sa7Amplification factor µ = 2.Dual TriodeUsed as a regulator tube in dc power-supply units, as a booster tube in the scanning circuit of television receivers,and as a push-pull class A output tube in high-fidelity audio amplifiers.

author: Johnny10
author_rank: Frequent Contributor
timestamp: June 05, 2017, 05:46:45 pm
content: Thanks everyone!I hadn't had my second cup of coffee before I posted.Afterwards I thought why not do an image search?I have 3 of these tubes that were given to me in a plastic container filled with old Tektronix tubes.Two were RCA and one Sylvania all with similar construction.
RCD clamp & Flyback converter - Page 1
Forum section: electronics / beginners

author: salviador
author_rank: Regular Contributor
timestamp: April 29, 2016, 09:04:50 am
content: Hi,I'm repairing a Flyback converter power supply.I have a low output voltage and low out power! (this is the problem)I find the capacitor of RCD clamp is damaged.It must be of 470pF and instead I measure 380pFMy question is,When it is important this capacitor? (only it serves for suppress Voltage Transient Spikes), but if capacitor is damaged the output voltage of power supply, It may be affected?Example RCD Clamp:

author: Richard Head
author_rank: Frequent Contributor
timestamp: April 29, 2016, 09:39:38 am
content: SalviadorThey are normally pulse grade capacitors. The dielectric is normally polypropylene (low loss dielectric) and the capacitor type FKP1.For small little flyback converters (<100W) you can get away with different dielectrics but they aren't the optimum type.Several manufacturers make FKP1 caps including Wima, Epcos etc.The snubber shouldn't affect the output regulation at all unless it's about to self-destruct.Dick
RCWL-0516 doppler radar microwave motion sensor re-trigger time? - Page 1
Forum section: electronics / beginners

author: YurkshireLad
author_rank: Frequent Contributor
timestamp: February 14, 2022, 07:47:34 pm
content: I've been experimenting with an RCWL-0516 doppler radar microwave motion sensor module -https://github.com/jdesbonnet/RCWL-0516/. I have it working but it only stays high for 2s when it detects motion.The documentation on this site say you can regulate the repeat trigger time; what is the repeat trigger time? Is it the time after returning to low before it will re-trigger if motion is still detected? Or is it the time it will stay high before returning to low?Thanks
RD6006 module runs off 44v CT transfo - Can CT be used for anything useful? - Page 1
Forum section: electronics / beginners

author: Cliff Matthews
author_rank: Unknown
timestamp: March 26, 2020, 03:19:42 am
content: I have a Riden RD6006 buck converter connected to a 44V-CT transformer, bridge and 12,000 uF of filtering.Can the transformer's Center-Tap be used as anything useful with respect to output terminals of the buck converter?I was wondering about using a LM337 regulator between (-) and CT as a virtual ground for <500ma..*Eg: Split supply==> Set Riden for 100ma and 24v, set LM337 (VG return path) at 200ma and 12V less than Riden (+)** Would an LM317 be the better choice? or are the results of this "hair-brained idea" doomed from the start?
RD6006P charging my first (expensive) battery questions? - Page 1
Forum section: electronics / beginners

author: jfharper
author_rank: Contributor
timestamp: October 28, 2023, 02:39:53 pm
content: So I've owned an RD6006PW 60V PS for a while and have used for Arduino voltages, but now need to charge a LifePower4 48V server rack battery to full SOC before setting up my off grid system. I've read (mostly) the Custom Firmware Document for the PS, and the spec sheet for the battery, and just want to double check I am going to do this correctly.1. The battery spec sheet states the following...from this, I set my V-Set to 56.2V...correct? I think I set the I-Set to the max of my ps which is 6A, since the batt can handle a lot more...I realize it will be slow.Voltage 51.2VCapacity 100AhCharging Voltage (Bulk/Absorb) 56.2V (+/- 0.2V)Float 54V (+/- 0.2V)Low DC Cutoff 47-44V (depending on load - start high, lower if needed)Charging Current Max Constant Charge: 100A (30-50A recommended)2. So this is my main question, the batt has built in bms for the cells, how should I determine fully charged? Should I set the cutofff cap or cutoff current to something high like 1A? There is some softare the batt manufacture has made available call BMS Test, so see what the BMS is doing...should I have this going during the charge? It shows SOC, charging state I think, cell voltages, and balancing, etc.3. Is there any other setting I should look out for before doing this?I was going to update the firmware to one if UniSoft's before proceeding just for kicks, but if this can be done without the upgrade that would save me some time and I can do it later when I have more.

author: m k
author_rank: Super Contributor
timestamp: November 10, 2023, 10:30:12 am
content: Since bench power doesn't stop you should stay low.As long as you are present 56.2V is fine, when you leave float 54V is better.50% charge is fine, your off grid system can continue from there.
Rd6018 power supply - current limit vs overcurrent protection? - Page 1
Forum section: electronics / beginners

author: ElectricPower
author_rank: Frequent Contributor
timestamp: October 01, 2021, 04:01:51 pm
content: Maybe a wery stupid question, but can someone explain to me what the difference is between current limiting and overcurrent protection is on the RD6018 power supply?My old power supply had only over current protection where i had to short the probes to adjust the current, but with RD6018 i can do it in two places.

author: bob91343
author_rank: Super Contributor
timestamp: October 01, 2021, 09:46:59 pm
content: The difference between overcurrent protection and current limiting is semantics. The former presumes that the power supply will not be damaged by excessive load current. The latter implies that the output current cannot increase beyond some specified limit.In your case, reading the manual doesn't help due to translation problems. Further confusion results because I don't understand your last statement.

author: Benta
author_rank: Super Contributor
timestamp: October 01, 2021, 10:20:17 pm
content: After leafing through the "user manual" I gave up.That "power supply" is apparently an accessory for an iPhone. I've never seen anything more ridiculous and unserious in my life. Concerning voltage and current specifications: ask on Facebook or Twitter. Which most likely won't help, but hey...

author: BrokenYugo
author_rank: Super Contributor
timestamp: October 01, 2021, 10:49:12 pm
content: Just looking at the front panel I'll hazard a guess the limiting is the usual CV/CC lab supply controls, and "protection" introduces a limit of how high either can be dialed to prevent accidents working with sensitive circuits. Play around with it and find out.

author: ElectricPower
author_rank: Frequent Contributor
timestamp: October 02, 2021, 01:47:52 am
content: Quote from: BrokenYugo on October 01, 2021, 10:49:12 pmI will do that. Thanks.

author: ledtester
author_rank: Super Contributor
timestamp: October 02, 2021, 01:50:04 am
content: Quote from: ElectricPower on October 01, 2021, 04:01:51 pmI would call that constant current regulation instead of overcurrent protection.Usually "protection" systems disconnect the supply from your load when the protection condition is detected and then require you to reset the system.The overvoltage/current protection limits might refer to the input voltage/current.

author: ElectricPower
author_rank: Frequent Contributor
timestamp: October 02, 2021, 04:20:53 am
content: Quote from: ledtester on October 02, 2021, 01:50:04 amAhh... i see. Thanks for that simple but great explanation.

author: ledtester
author_rank: Super Contributor
timestamp: October 02, 2021, 03:29:23 pm
content: btw, there's an excellent ongoing RD60xx thread here:https://www.eevblog.com/forum/testgear/ruideng-riden-rd6006-dc-power-supply/Look for posts by "Unisoft" -- they have created new firmware for these devices.

author: ElectricPower
author_rank: Frequent Contributor
timestamp: October 05, 2021, 05:06:36 am
content: Quote from: ledtester on October 02, 2021, 03:29:23 pmThank you wery mutch!I will follow this thread
RDS Encoder... Brand New But Older - Page 1
Forum section: electronics / beginners

author: sos_radiogear
author_rank: Newbie
timestamp: October 13, 2024, 03:41:01 am
content: I know that Clear Channel used these to to add weather /traffic to their broadcast. I found similar units ranging in price from $300 to $1700 but nothing identical. I have 3 brand new units. If not trash, any idea what they are worth? Thank you!
RDTech DPS5005 power supply with USB/BT serial port pin out? - Page 1
Forum section: electronics / beginners

author: BeBuLamar
author_rank: Super Contributor
timestamp: December 01, 2023, 11:35:00 am
content: I want to order the DPS5005 with the bluetooth and USB option. I understand that the unit has a serial port and then it comes with 2 converter boards to convert to either bluetooth or USB. Now that I don't need either BT or USB but I need the serial port. I have 2 questions1. Is the port RS-232 or RS-485?2. What are the pin out? The unit comes with the cable to connect to the BT or USB board and the cable has 4 wires? Which wire is which?

author: electr_peter
author_rank: Unknown
timestamp: December 01, 2023, 10:10:17 pm
content: IIRC, it uses TTL levels. Pinout can be checked by measuring (it is only for wires VCC, GND, TX, RX). In fact, it is possible to use both USB and BT adapters by duplicating all wires (except RX, which should be switched).
Re-branded oscilloscopes? - Page 1
Forum section: electronics / beginners

author: YurkshireLad
author_rank: Frequent Contributor
timestamp: February 23, 2021, 03:08:30 pm
content: I noticed that the Multicomp MP720010 looks like a re-branded OWON SDS1102, or vice versa. When a company re-brands an oscilloscope, are they identical or do they make modifications to the original internal design? If I bought this Multicomp, am I getting an Owon and vice versa?https://cpc.farnell.com/multicomp-pro/mp720010-eu-uk/digital-storage-oscilloscope-50mhz/dp/IN08385https://www.ebay.ca/itm/OWON-SDS1102-Oscilloscope-Multi-version-2CH-Digital-100MHZ-Bandwidth-1GS-s-Accur/261761536711

author: tunk
author_rank: Super Contributor
timestamp: February 23, 2021, 04:06:41 pm
content: I guess you have to check the specs, if they're thesame then a guess is that they are identical. Lookslike you can find them branded as Hanmatek, Mustool,Cdek, Peaktech and probably a few others as well.

author: ataradov
author_rank: Super Contributor
timestamp: February 23, 2021, 05:40:50 pm
content: SDS1102 is probably the most rebranded scope ever. They all are the same, just the logo changes. They also cost about the same, so pick whatever is available locally.

author: CaptDon
author_rank: Super Contributor
timestamp: February 23, 2021, 06:11:59 pm
content: Also important, who will fix it when it is dead right out of the box or dies within the warranty period?? Will you have to ship it back to China and never see it again for 6 months and when you get it back will it be only slightly less dead than it was? I freaking hate this chinese Agilent and LeCroy knockoff stuff. Maybe the Chinese do make the Agilent and LeCroy name brand stuff and then sell the crippled stuff under knockoff brands. We had to return 2 Rigol scopes dead right out of the box. Finally the third one worked. It looks like the big name scopes, but it doesn't have the feel, seems like inferior quality buttons and rotary encoders. Overall they feel like fallouts from the big name assembly line.
Re: Flir E4 Thermal imaging camera teardown - Page 1
Forum section: electronics / beginners

author: Sali
author_rank: Newbie
timestamp: March 18, 2018, 05:05:00 pm
content: Hi there!Can anyone help me with my problem please?I hacked my flir e4 recently and everything works just fine except one thing: temperature scale has only automatic mode..Any ideas?thanks.

author: Bud
author_rank: Super Contributor
timestamp: March 18, 2018, 06:06:42 pm
content: You did not anything about you camera.

author: Sali
author_rank: Newbie
timestamp: March 18, 2018, 06:12:45 pm
content: What u mean?

author: Bud
author_rank: Super Contributor
timestamp: March 18, 2018, 06:18:04 pm
content: I just noticed you cross posted in several threads. Post in one thread.We do not know the history of your camera, if you bought it used or new, we don't know your firmware version.

author: Sali
author_rank: Newbie
timestamp: March 18, 2018, 06:25:22 pm
content: Sorry, i didn't mean it, just don't know how to get rid of this thread. Just wont remove.It's a brand new camera, 2.0L, 3.9SW.I followed your instructions, and everything went fine. Everything working great except temp scale...I checked config file few times and didn't find any mistakes...

author: Bud
author_rank: Super Contributor
timestamp: March 18, 2018, 06:50:33 pm
content: Since this is 3.9.0 please continue in the WiFi thread. This thread should be locked.@mods: can you please move this to Flir E4 WiFi thread.
re: newbie intro and question for Sydney-siders - Page 1
Forum section: electronics / beginners

author: inwo
author_rank: Newbie
timestamp: October 01, 2016, 12:14:15 pm
content: hi allmy name is David. I live in Sydney and have an interest in electronicsi bought a cathode-ray oscilloscope [cause they are awesome] off a chap in Kellyville through Gumtreeit works! also he told me the scope has never been calibrated, he is the original owner - it appears it has gathered dust in his garage since the 80'smy question,does anybody know who calibrates cathode-ray oscilloscopes in Sydney?make: Trio model: CS-1040, triple trace oscilloscope - 40MHzalso, i have the complete service manual. im afraid to calibrate it myself, i would prefer a pro do it..regards
Re using parts. - Page 1
Forum section: electronics / beginners

author: ionicwake
author_rank: Newbie
timestamp: June 02, 2017, 09:53:24 am
content: how do you guys re use parts? for instance i have this little amp board i pulled from a tv and i want to use it in a diy bluetooth speaker. i have been unable to find a pin out for the board but have found one for the little TDA8931 on the bottom. i also have an lcd display with a touchscreen digitizer installed. i can get the lvds connections figured out but not the touch screen. how do you guys find information on scavenged stuff?thanksIonthe amphttp://i653.photobucket.com/albums/uu252/ionicwake/20170602_034332.jpg

author: Rerouter
author_rank: Super Contributor
timestamp: June 02, 2017, 10:19:39 am
content: For the amplifier, as it has a plug for power and the speakers, you should only need to trace back the input signal from the chip on the bottom to the pins,For your touchscreen, does it have a controller for the touchscreen, or 4 terminals,Is it likely a resistive or capacitive one?For a resistive one, you can measure with a multimeter as you move your finger across the screen, 2 wires will be X, 2 will be Y.

author: Shock
author_rank: Super Contributor
timestamp: June 02, 2017, 01:03:37 pm
content: The easiest way is the original schematic of the device the pcb came from. If those are impossible to find datasheets may contain sample circuits.Such as in your case identify pin 4 on the IC and then probe continuity between that and close resistors working outwards. When you find a low resistance path measure and record the component value. You can soon build up an idea of how they are using the IC, especially if several sample circuits to choose from.For more complex circuits you might have to reverse engineer, one simple way is taking photos and a using graphical editor to draw a transparent layer of the tracks so you and fashion it back into a readable schematic. There are tools for creating and optimizing pcb manufacture that can be used to help recreate schematics as well.

author: ionicwake
author_rank: Newbie
timestamp: June 03, 2017, 12:41:52 am
content: thanks for the tips guys/Gals
Re: what to do with a HDD motor - Page 1
Forum section: electronics / beginners

author: T4P
author_rank: Super Contributor
timestamp: July 17, 2012, 04:51:55 pm
content: Quote from: KTP on July 16, 2012, 10:20:10 pmI actually felt more guilty than you did to use it as a frisbee!FE:but really i am not a fan of cloud for reasons : Distance towards cloud, internet speed ...
Read chip for "K-type" temperature sensor, with an I2C output - Page 1
Forum section: electronics / beginners

author: w_leds
author_rank: Contributor
timestamp: May 20, 2017, 10:09:34 am
content: Hello I would like to know if there is a chip that is able to read the temperature sensors type K but with an output in I2C. Thank you in advance for the answerscordially

author: jeroen79
author_rank: Frequent Contributor
timestamp: May 20, 2017, 12:51:15 pm
content: Google comes up with TMP513.Or MAX31855 if SPI is good too.
Read ST93C86 - Page 1
Forum section: electronics / beginners

author: Qu!cK
author_rank: Newbie
timestamp: May 13, 2015, 05:53:34 pm
content: Hello,I need some help, i'm trying to read a ST 93C86 from my VW Dashboard to get back my Immo pin.I bought an EZP2010 but actualy the eeprom is not detected or not supported.Do you know a reader than can read a ST93C86 ?ThanksCheers from Bordeaux - France.

author: wraper
author_rank: Unknown
timestamp: May 13, 2015, 06:01:22 pm
content: If it really cannot read it, IC should be dead. This programmer definitely supports 93C86. What means not detected? Don't you try to autodetect it by chance?

author: Qu!cK
author_rank: Newbie
timestamp: May 13, 2015, 06:28:46 pm
content: The IC work, the dash work perfectly.Autodetect don't found also.It's a ST93C86 WP , i don't knwo if the WP make any change...

author: wraper
author_rank: Unknown
timestamp: May 13, 2015, 06:54:00 pm
content: Autodetect is only for parallel eproms. It can destroy all other ICs. BTW this should be M93C86WP made by ST, not ST93C86WP. I cannot find the datasheet from ST but here is from Catalyst. According to it, W might mean different order of pins. Check the actual PCB for what pinout variant power pins do match. If there is no M93C86W (or J) or CAT93C86W(J) or any93(C or whatever)86W(J) in the IC selection list, then you can just make an adapter on the breadboard or just with wires, or whatever to match the pinout commonly used for 93C86.

author: Qu!cK
author_rank: Newbie
timestamp: May 13, 2015, 07:06:16 pm
content: I have no 93C86 in the ST 93 EPROM list in EZP2010... I use also an Clip connector to read the eprom on dash pcb.

author: wraper
author_rank: Unknown
timestamp: May 13, 2015, 07:14:18 pm
content: Quote from: Qu!cK on May 13, 2015, 07:06:16 pmThen select 93C86 from any other manufacturer (type 93c86 in search). They basically are the same from all manufacturers (except that case with different pinout on CAT93C86W). Clip connector very likely won't work and you will need to desolder the IC as circuit around the IC will prevent normal operation of programmer.

author: Qu!cK
author_rank: Newbie
timestamp: May 13, 2015, 07:38:47 pm
content: Yes i try with 93c86 from ATMEL CATALYST etc...I receive my soldering station tommorow i will try , thanks for help
Reading a 4N35 optocoupler datasheet - Page 1
Forum section: electronics / beginners

author: Lucky-Luka
author_rank: Unknown
timestamp: February 26, 2020, 10:19:17 pm
content: Hi allIs there a good samaritan that can help me understand1)How fast can I drive this optocoupler?2)Input voltage? Is it 1.2V?3)Which current and voltage its output can handle? (Less than 50mA and less than 70V? How much less than those values?)Cheers

author: coldfiremc
author_rank: Regular Contributor
timestamp: February 26, 2020, 10:59:23 pm
content: If is for switching, 50 usecs is the turn-on turn-off time. This in the kilohertz order. If not, look for capacitance and make a frequency response approximation of it. Gain will decrease considerably beyond the cutoff.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 27, 2020, 06:58:14 am
content: You candriveit as fast as you like, it's just an LED. Use a current limited driver, and expectabout1.2V drop but do not rely on that voltage to be consistent, as it varies inversely with temperature and logarithmically with current. Hence the current limited driver.What you get at the output, however, is limited by physics of the phototransistor. At best, you can use it in photodiode mode, which is good for a few MHz. This requires a carefully designed amplifier.As a phototransistor, yes, expect 10s of us for switching speed. The best case is with almost no voltage swing, which is where they do the test with a 100 ohm load resistor. With practical values (~kohms), it's very slow, 50 or 100us.Speed can be improved somewhat by connecting a resistor across the base and emitter pins. 47k to 100k typically. This destroys CTR at low currents, and still reduces it pretty significantly at full I_f. But you can get more like 10-20us switching speeds, with typical (say logic level?) voltage swings, this way.Output current and voltage shall stay within the specified limits, yes. Power as well, that is, the product of Vce * Ic. It's not rated for much, so be careful. In saturated logic applications, this isn't a problem.Tim
Reading a Chip code - Page 1
Forum section: electronics / beginners

author: Prog
author_rank: Newbie
timestamp: July 28, 2016, 08:29:07 am
content: Hey there,We have these chip types:W25Q128FV, W25Q128FV [WSON 6x5], W25Q128FV [TFBGA24 6*4], W25Q128FV [WSON 8x6], W25Q128FV , W25Q128FV , W25Q128FV , W25Q128FV [TFBGA24 5*5]Source:here.In the Winbondmanual, page 97 we have some guides but in my case 25Q128FVIQthe x code is missing. This is the standard version (W25Q128FV) or is not supported?Any documentation regarding the chip code reading will be appreciate it.Thanks,

author: gnif
author_rank: Unknown
timestamp: July 28, 2016, 09:09:40 am
content: It is the same part, just special options, page 96 shows what they mean, in your caseI = IndustrialQ = Green Package with QE=1 in Status Register-2If these designations are missing then it is not the 'Green' package, ie, uses leaded solder.It also states the W and I indicators are not marked on the part.
Reading a color-coded tantalum capacitor? - Page 1
Forum section: electronics / beginners

author: snuci
author_rank: Newbie
timestamp: June 29, 2015, 05:42:37 pm
content: Whoohoo! I finally have a question after much lurking here.I am a vintage computer collector and fix items here and there as well as replace capacitors both because of a need to replace a bad one and for preventative maintenance (to avoid corrosion of leaky caps). Yesterday, I ran into a color-coded tantalum capacitor that has me confused on how to read it.I have an old PerSci floppy drive with dual controller boards from the early 80's. I put it into an old S-100 system and shortly after power up, the "magic smoke" was released from one of these caps. I immediately powered down. Below is a picture of what's left in the area marked C12 (or C13).There are other caps that are similar so I've included a picture of another cap with the same markings. After looking athttp://www.csgnetwork.com/capcctantcalc.html, I believe it to be 10 uF @ 16volts if I read it correctly but the little picture says 1Uf @ 16v so I'm a little unsure if the blue line denoting positive is a multiplier or not. Does someone know how to read it?Thanks in advance.
Reading a li-ion with a 1v adc - Page 1
Forum section: electronics / beginners

author: solexious
author_rank: Newbie
timestamp: February 29, 2016, 12:59:09 pm
content: Hello all,I'm trying to read the voltage of my power source for my esp8266 with its inbuilt adc. Ideally I want to use as full of the 0-1v range of it's adc so a simple voltage divider doesn't seem to be the answer to my problem.Is there a better technique for reading 2.8-4.3v with a 0-1v adc?CheersSol

author: jeroen79
author_rank: Frequent Contributor
timestamp: February 29, 2016, 01:46:20 pm
content: Why would a voltagedivider not work?Just scale it down so that the max input is less than 1V and then scale it back up in the software.

author: solexious
author_rank: Newbie
timestamp: February 29, 2016, 02:07:09 pm
content: Quote from: jeroen79 on February 29, 2016, 01:46:20 pmI would if I was wanting to read 0-4.3v but ideally I want to use the adc's full range to read 2.8-4.2v rather than lose resolution scaling it up in software.

author: jeroen79
author_rank: Frequent Contributor
timestamp: February 29, 2016, 03:25:56 pm
content: Put a zener diode between the + and the voltage divider to take 2.x V off the battery voltage.

author: hamdi.tn
author_rank: Frequent Contributor
timestamp: February 29, 2016, 10:43:38 pm
content: one option is to use basic opamp circuit and a couple of resistances will do that for you ... subtract Vbat - 2.8V with a differential than apply that to a voltage divider of 1/1.4second, if you can change the negative voltage reference of the adc, then move it up to 2.8V and scale down your Vbat by 1/1.4
Reading a NAND Flash - Page 1
Forum section: electronics / beginners

author: 00pointer
author_rank: Contributor
timestamp: May 12, 2019, 01:54:12 pm
content: Hey,I am looking to read a Nand Flash from Micron to dump its data.It is a MT29F1G16ABBDAHC flash and I am looking at these eMMC flash readers/writers and wondering which one works with it. There are multiple product in the market such as eMMC100, Emcp221 which each of them have their own sub-models as well. Does anybody know which device is appropriate for reading content of this NAND flash?The package of my nand flash is a 63-ball VFBGA, 10.5x13x1.0 size.Looking forward to hear back from you guys