Forum - Recent Threads

Resistor and Capacitor ID

RLM431 — Fri, 30 May 2025 00:41:54 GMT

Hello

New to the site. I’m no engineer and not an avid electronics enthusiast but I tinker with things. I can research and typically find an answer but I’m having a little difficulty with 2 capacitors and 1 resistor. They’re from an old marine tachometer I’m trying to bring back to life. I’m looking for some help identifying them and suitable replacements. I have attached a couple of pictures.

Any help is very much appreciated.

- RL

/resized-image/__size/1280x720/__key/communityserver-discussions-components-files/36/IMG_5F00_1303.jpeg

/resized-image/__size/1280x720/__key/communityserver-discussions-components-files/36/IMG_5F00_1316.jpeg

/resized-image/__size/1280x720/__key/communityserver-discussions-components-files/36/IMG_5F00_1314.jpeg

Any help on the following low pass filter scenario would be very much appreciated.

k.morrow — Thu, 24 Oct 2024 16:25:11 GMT

Objective: To build a shielded cable with a passive low pass filter to be used for connecting the ground connection of a typical US 120V socket or from an earth ground rod to a bed sheet with silver threads in it for grounding or earthing purposes. The purpose is for the filter to eliminate any/all AC noise from going up the shielded cable and getting to the bed sheet.
For testing possible filter configurations I have a Fluke 179 True RMS multimeter and an old Hitachi V-152F-15MHz Oscope and a BK 3011B - 2 MHz Function generator.

My thoughts are to use a single resistor with an electrolytic capacitor so when measured with the multimeter in one direction I would measure the resistor value and in the other direction I would measure an infinite impedance.

I have explored several online low pass filter calculators:
www.redcrab-software.com/.../RC-Low-Pass-Filter
sim.okawa-denshi.jp/.../CRlowkeisan.htm
learningaboutelectronics.com/.../Low-pass-filter-calculator.php
markimicrowave.com/.../

I have a few questions:
1. Do I make the filter with a cutoff frequency of 60Hz or something very low like 1Hz or less?
2. Is an RC filter best or use an RLC or some other config?
3. Could the filter be better with a 2nd order (or 3rd, or 4th ...?).
4. For the filter connected to a shielded cable, are surface mount components better to use than leaded components?

Thank You!!

My photocell for outdoor lighting does not light up if power went during off the day

cksimkoza4 — Thu, 11 Jan 2024 23:42:10 GMT

and it comes during the night.what could be the problem

drive.google.com/.../view drive.google.com/.../view

Can someone help identifying what this are? I reckon it is an old diod. Need something to replace it with

kardan — Sat, 25 Nov 2023 22:32:14 GMT

The simple markings on photo does not have the Anode and Cathode marked.

Please reload the page as I have updated the last image.

Dealing with Unexpected Emissions: The Fellowship of the Ferrite Ring

shabaz — Fri, 18 Aug 2023 17:31:07 GMT

I was experimenting with bits of circuit, hopefully, to become a power supply eventually. It is a work in progress.

At this stage, I’m using bits of scrap copper-clad board, each with a sub-module. It’s too early for a PCB.

However, during the prototyping, I noticed (amongst other issues that I need to solve!) a particular artifact on the ‘scope trace when looking at the output.

This situation ended up being a good example of where it pays to zoom out and look at a lot more of the spectrum view than expected!

Admittedly this was a lot easier to identify using the MXO 4 ‘scope, but it would be possible to spot with other test equipment, such as a spectrum analyzer and a near-field probe. I just used the normal 'scope probe, I didn't do anything special.

With the MXO 4, the anomaly was zoomed in, and then using a logarithmic-frequency spectrum view, it was possible to see the extent of the problem, with the left side of the spectrum view showing the wanted oscillation (fundamental frequency) and its harmonics, and the right side showing the spurious output.

Now I could try to do something about it!

I used tiny ferrite rings (legend has it they were forged by Fair-Rite, part code 2643001501 ) on the base input of the transistors. Essentially, they act as a bit of additional resistance for the higher frequencies. The rings cost $0.02 currently (although more expensive in the UK).

Back to the ‘scope:

Much better!

As mentioned, I still have other problems to deal with, but I thought it was a nice example of why it makes sense to do testing to frequencies far higher than expected, just in case there are spurious emissions, and why it can be a good idea to possess the rings because one never knows when they are needed.

Thanks for reading!

Need SOLDERING (non PCB) Projects Using This 6-pin HKE Relay, Preferably an Automatic Light With an Ldr.

Pinto_Marcelo — Wed, 19 Jul 2023 19:13:00 GMT

Hello world, I'm new here, and I tried to search for some projects with this Relay but I couldn't find it.

I would love to solder circuits WITHOUT PCB, like this: www.youtube.com/.../Rm68zeCjxLg

preferably an automatic light with an ldr.

I've been studying this datasheet, but it doesn't work like other relays...

Thank you!

As you can see, this 6-pin relay has no diagram.
And these pins I soldered trying to do a test.

Hey, Guys, I'm stumped It

phoenixcomm — Thu, 06 Apr 2023 16:36:11 GMT

Ok, it claims to be a 0.22Ω 3watt power sand resistor, with 3 legs. (so starting at the top and going clockwise, 1 at the top, 2 on the right, and 3 on the left)

My fluke 113 says no it's 0.38Ω between 1 and 2, as well as between 1 and 3, and 0.59/0.60Ω between 2 and 3.

My HP3435A set on the 20Ω scale says it's 0.37Ω between 1 and 2, and 0.38Ω between 1 and 3, and 0.59Ω/0.60Ω between 2 and 3.

Something is not right.

and Please look at the logo, so I can figure out who made the stupid thing..

oh btw the wires go all the way through the body and are about 1" long on the reverse side.

Thanks again. Cris

Help finding Resistance formula

Psin545 — Tue, 17 Jan 2023 04:14:59 GMT

I would like to get some help trying to figure out the resistance from a specific point in this circuit.

If the top left corner of the square was point A, and the top right corner was point B, the bottom right corner is point C and the bottom left corner point D,

and if R1 is the top resistor, and R2 the resistor going down the right side, and R3 is the bottom resistor, and R4 is the left resistor, and R5 is the one cutting across the square,

what is the formula to calculate the resistance between point A and C? I’ve calculated all other points (AB,AD,BC,BD, and CD) but can’t seem to get it correct for AC.

Any help is greatly appreciated. (Sorry for the lack of better photos and diagrams)

Need to replace resistor 900 ohms / % Tolerance

Alex-andre — Mon, 28 Nov 2022 08:33:15 GMT

Hello there,

I need to replace this resistor which appears to be a 900 ohm with a % tolerance. (4 rings = Black / White / Red / Silver or Grey and around 25mm long)

I bought one with almost same features (OHMITE OX102KE Through Hole Resistor, 1K ohm, OX, 1W, ±10%, Axial, 300V) but it doesn't fit, it's far too small compare to the one I need to replace.

Do you have any suggestion where to buy or how to replace it ? 

I attached a picture below.

Thanks a lot

Alex

Audio Tweaking

michaelkellett — Mon, 14 Mar 2022 10:47:05 GMT

E14 have been kind enought to reward me for my contribution to the recent

Audio Tweaker's Wishlist - What do I need to build/maintain audio gear?

thread.

These turned up today:

Thanks very much.

Pinout of SMD 2520 crystals from Multicomp Pro

anonymous_engineer_8hflg — Mon, 10 Jan 2022 02:09:42 GMT

Element14 lists some multicomp pro branded crystals in 4 pin packages. The datasheet describes them like they are passive crystals, specifying shunt/load capacitance and ESR.

The datasheet includes package drawings and model numbers, but no pinout information. One of these is model MCSJK-7E-32.00-10-30-60-B-30.

Is the pinout for that series the same pin 1 + pin 3 pinout as in the SMD3225 crystals, also from multicomp pro. The somewhat similar Murata crystal datasheet specifies pinout and quality test procedures, but forgets to specify if their pinout drawing is top view or bottom view.

Or is the pinout the same pin 1 + pin 4 pinout as in 32.767 kHz crystals from Rami Technology?

In either case, actual pinout information is needed to use these parts PCB design for products.

Fluid Control Solenoid Unusual Readings

jw0752 — Fri, 12 Feb 2021 18:58:18 GMT

This is the coil from a solenoid that is used in a dental counter top sterilizer. When it is energized it pulls a plunger away from a valve seat and lets water flow through the valve and into the sterilization chamber. While I was working on a sterilizer a while back I got some really strange readings on my ohmmeter when I attempted to verify continuity in the coil of this solenoid. Further tests on other coils in other sterilizers showed that my unusual readings were consistent with this style solenoid.

As one can see from the label this coil is designed for 120 Volts 50 to 60 Hz and is rated at 14 Watts which would indicate a current draw of approximately 100 mA and a DC resistance of approximately 1K Ohms.

The Ohms reading I was getting however from various digital meters was more in the area of 500K Ohms. I hooked the coil up on the bench and applied 115 Volts AC to it and got a current reading of about 100 mA as expected. Still the digital meters all said the resistance was 500K Ohms. When I tried using one of my analog Ohmmeters I got a resistance reading of about 800 Ohms. The coil was acting very much as if there was a semiconductor junction in series with the coil. I had seen this before when I have attempted to read polarity on a diode using the Ohms scale of digital meters. The digital meters do not use a high enough test voltage to overcome the junction energy level and therefore do not give an accurate reading. The analog meter on the other hand uses 3 volts and therefore can read the resistance past the semiconductor.

I continued my tests by reversing the polarity of my test leads and found that there was no noticeable polarity discrimination. I got the same 800 Ohms on the analog meter and 500K on the digital meter regardless of the polarity of the test leads. When I switched the digital meter to Diode Test it told me that the energy barrier that I was dealing with was about 1.9 Volts. This would be close to three Si diodes in series with the coil and since there was no polarity preference there must be an additional 3 Si diodes reverse polarity in parallel with the first three diodes.

Now I have no way of knowing if these are standard diodes or some other semiconductor such as a NTC or PTC Thermistor or some other type of semiconductor. Whatever it is, it is molded into the plastic shell that is formed around the coil itself and not visibly evident.

I attempted to find data sheets on the coil from the manufacturer but there was nothing to indicate that it is anything other than a simple coil.

My question is: Does anyone have any idea of what type of semiconductor might have been put integrally in line with the coil of this solenoid and what purpose would it serve? Does my analysis of this actually being a semiconductor in series with the coil make sense? Are there any other possible explanations?

The solenoid, when in operation, must dissipate the 14 Watts that is generated by it and it is in an already hot 80 degree C environment. The fluids flowing through it are as hot as 100 C. Other than being in a hot environment and handling hot fluids there is nothing really unusual about the solenoid. Also in recent models of this sterilizer a different solenoid is being used that does not have the anomalous readings of the older style solenoid. The new solenoid has a roughly 1K DC resistance that is readable by both the Digital and Analog Ohm meters.

Any insights will be appreciated.

John

Help identifying this part please, can't find a replacement

charlie292 — Tue, 28 Apr 2020 18:27:12 GMT

Can anyone help me identify this part? I think it's actually a resolver rather than an encoder.

It's from a radio stack for a flight sim, made by Precision Flight Controls. I have a couple that are snapped and some that have stopped working all together.

I've Googled all the numbers etc I can see on it but keep drawing a blank, I've included some photos please see attached, if the part is now obsolete can someone point me in the direction of a suitable replacement?

Thanks all.

Attachments:

Information on the clear connection film to an LCD display

jw0752 — Wed, 22 Apr 2020 23:19:23 GMT

I have recently been asked by a friend andriu011 how to improve the connection of the clear film ribbon between a glass LCD display and a circuit board. Frankly I do not even know the technical name of this type of connection cable. I have seen them and been frustrated by them when they have lost their connection. Usually pressure is applied to the back of the film against the glass to make the connection to the LCD circuits in the glass. If anyone knows what to call this technology so I can google it and learn more it would be appreciated. Also if you have any suggestions for cleaning the connections or improving them please tell me.

John

Male/female pin converter?

madbilly — Tue, 04 Feb 2020 12:57:18 GMT

Hi everyone,

First, this is my first post in element14 so I don't know if there is a better subforum for my question - if there is, then mods please move it there.

I'm trying to find some pin converters, by which I mean something which will change a male pin into a female socket. This is primarily for stacking shield boards on top of a microcontroller board when I've got the wrong sense pins soldered in and don't want to change them. For example, I have two boards which I want to stack, both have male pins, so how do I connect them? I've looked around a lot of sites trying to find these but haven't succeeded yet and when I was thinking of where I could ask element14 seemed like the logical choice.

Helpful suggestions much appreciated.

Cheers

Replacing hole thru to surface mount

kaos4u — Wed, 15 Jan 2020 18:58:54 GMT

Can you find a good replacement for:

2700pF 1.6KV PP

B32671L1272J000B32671L1272J000

Regards

How to test this transformer?

sebnast — Tue, 24 Dec 2019 11:16:17 GMT

Hi, I need help testing an inverter board transformer, I don't have much experience with this type of transformer and I'm not sure how to test it, I will be forever grateful for any suggestions.

the part is: TM-09175

photo attached.

Thanks

Seb

Why are the Triac Snubber Resistors Failing in this circuit.

jw0752 — Mon, 23 Dec 2019 04:08:23 GMT

I have recently been repairing power supply / control circuit boards for a small machine that cuts tape to a specified length. Here is a picture of the circuit board in question along with my notes so far:

Here is the schematic that I have reverse engineered from the circuit board:

I have been working my way through a box of circuit boards, that were replaced in the past as black boxes, and repairing them. I have noticed that on almost every board the 150 Ohm 1/8 Watt snubber resistors are open or showing meg ohms of resistance. I have done the math for the circuit and with our local 120 volt 60 Hz line voltage the .1 uF cap in series with the 150 Ohm resistor should have 4.5 mA of current and a corresponding 3 mW of power delivered to the resistor. Since the resistor appears to be an eighth Watt there should be plenty of room for it to handle this voltage, current and wattage.

Unfortunately I am finding almost 100% of these 150 Ohm snubber resistors failed. There are more of the same 150 Ohm 1/8 Watt resistors used on this board in other parts of the circuit but the only ones that are failing are in the snubber circuit.

I am hoping that someone with more experience than me can tell me what is going on in this circuit that is taking out the snubber resistors. The Triacs drive a Variable direction motor and a large solenoid so the loads are definitely inductive. The little resistors do not look heat damaged. They also do not look to be of high quality if that may be a contributing factor.

Any insights you may have will be appreciated.

John

Design Challenge Preview: Are You Ready To Experiment with Inductors?

rscasny — Fri, 27 Sep 2019 21:02:00 GMT

I guess my Poll: Do You Know The Scientists Who Developed Classical Electromagnetic Theory? and the newly launched Inductors Quiz probably were hints that something else was coming up for the community on the topic of inductors. Right you were!

Experimenting with Inductors

In several weeks, we will be launching a design challenge called, "Experimenting with Inductors." It will be similar to the contest we ran on polymer capacitors. The challengers will be sent a kit of inductors and ask to write two blogs: the first blog will describe what inductor experiments they want to conduct; the second and final blog will show the results of their experiments. The best blog will be the winner. We have a great prize lined up for the winner.

We will provide 10 people an inductors kit. The inductors will come from the KEMET MPX Series. These inductors are metal composite inductors used in DC to DC switching power supplies, as power inductors as well as EMI filter inductors. The metal composite core has high saturation characteristics maintaining function in rush current mode and characterized by temperature stable inductance. Click here to learn moreClick here to learn more

Here's the kit we plan on putting together for the experimenters:

So, what will your inductor experiments be about?

An experiment is just that: you want to test some characteristic of the component. To compete in this competition, you don't have to build or design a wholly new circuit. (You can if you want,.) You just have to experiment with it and write about it. To generate some ideas of what previous comonent experimenters did, go here: Grand Prize Winner's Announcement: Experimenting with Polymer Capacitors

What Do You Think of Stretchable Supercapacitors?

rscasny — Sat, 31 Aug 2019 23:55:01 GMT

Stretchable supercapacitors are another energy storage innovation that is destined to provide power to wearable electronics. Coined as "stretchy power sources," these stretchy supercapacitors are made with graphene and can be woven into clothing. The hope is that they can power bio-monitoring wearables, LCDs, and even "soft robots that wash your dishes," according to the American Chermical Society.

So, are you ready for the world of stretchy power sources?

Stacked Inductors ? Transformers ?

jw0752 — Thu, 29 Aug 2019 02:53:24 GMT

These stacked inductors are often found in upscale switch mode power supplies and I would like to understand them better.

In these stacks there has been some attempt to close and isolate the magnetic fields of the adjacent coils. You will note however that the top and bottom ferrite pieces do not actually touch. This is more evident in the smaller stack. Is there intent in this design or does the coil just happen to be wider than the ferrite could accommodate? Are these really transformers?

I have also seen the coils stacked as they are in the following picture with no attempt to close the magnetic field which makes me believe that they are probably transformers but I do not know.

If anyone has any insights or knowledge of these interesting configurations I would be very interested in learning.

John

Looking for this part

cstukel — Tue, 02 Jul 2019 18:28:51 GMT

Looking for this specific part, that connects to a resistor. Let me know if you know where to find it. Thanks

Heads Up: Experiment with some Polymer Capacitors and You may Win a Keysight O'Scope

rscasny — Wed, 27 Mar 2019 20:19:24 GMT

I have been talking up polymer capacitors on the community for the last few months.

I first started with a quiz: Polymer Capacitor Quiz Plenty of members joined in and took the quiz. I think they learned something in the process. I surely did, writing the quiz. I think we handed out 40 or so T-shirts to those members who scored 100%.

Then when produced two polymer capacitor videos with the help of VCP baldengineer and element14 presents. If you haven't watched them, by all means, please do. They are informative and enjoyable way to learn about polymers.

I have a webinar in the works, called Designing Circuits with Polymer Capacitors. It will dig into circuit design using polymers. Should be interesting. Hopefully it will appear in May. Stay tuned to the Webinars, Training and Events group.

But right now (meaning TODAY) we launched a special kind of Design Challenges . It's called Experimenting with Polymer Capacitors. Let me tell you about it.

This is a different kind of Design challenge, which the element14 team, sometimes calls a "mini-challenge." In this challenge, we are looking for our members to experiment with polymer capacitors in any way they desire. I'm sure there will be a few people who build or modify circuits with polymers. I think others could breadboard basic circuits with polymers. Given the fascination with soldering on the community, some members could experiment with soldering polymers (and produce some videos or their feat). I'm sure there are many other ways you can work with polymer capacitors that will be a learning experience.

What will you get for your efforts?

First off, ANYONE can play in this challenge. All you need to do is include at least 1 capacitor from the official kit, write 2 blogs, and you are in the running for a brand new Keysight O'scope.

Our judges will select the best blog that details the experiments and shares what they learned about polymers. It's that simple.

If you want to compete for a free Capacitor Kit + Tester, complete an application.

To learn more, please go to here: Experimenting with Polymer Capacitors

Randall Scasny

-element14 team

Special Purpose Inductor

jw0752 — Sat, 23 Feb 2019 05:20:29 GMT

Tonight as I studied a power supply circuit board I came across an unusual inductor. I can speculate that it is designed for high current and high frequency but I really don't know. I am hoping to learn more about it. Can anyone give me some insight into the reasons for the design characteristic which includes heavy multi-strand wire for the conductor (roughly 1.5 mm diameter 18 AWG?). Here are a couple pictures of the inductor which has a very stable inductance of 100 uH when tested up to 100 kHz.

In the circuit it was in series with the collector of a PNP MJE253 Power transistor.

Any insights would be educational.

Thanks John

Seeking Your Opinion: The Proposed Kit for the Polymer Capacitor Projects Scheduled for March

rscasny — Mon, 11 Feb 2019 22:33:52 GMT

As part of my interest in providing learning experiences and useful information to the element14 community on polymer capacitors, I am planning for March a polymer capacitor project with a free kit.

My goal is to get some polymer capacitors in your hands and have members build any kind of capacitor project. It can be anything as simple as an RC circuit to something more involved like a power supply. It's up to you. It would be nice to see some of caps I include in the kit used in the project. Now, I won't be providing everything for a project build--just the capacitors, a parts box and (hopefully a cap/ESR tester, depending on what my boss agrees to budgetwise).

I figure I will get a lot of opinions on this. That's fine; all of your opinions are usually very interesting! Again, my goal is get everyone more familiar with polymers and I think getting some in your hands, not matter what the projects are, will be a benefit to the community.

So, here is what I am proposing. I'm just pasting in the links. Tell me what you think.

Parts Box

https://www.newark.com/duratool/d00413/box-storage-18compartment-transparent/dp/58M5457?st=tool%20enclosures

Capacitor tester

https://www.newark.com/peak/72-12835/esr-meter-capacitor-1to-22000mf/dp/56Y1286?st=capacitor%20tester

Polymer Capacitors

panasonic

https://www.newark.com/panasonic-electronic-components/10tpe47mazb/cap-tant-polymer-47uf-10v-case/dp/86Y4986

https://www.newark.com/panasonic-electronic-components/35svpf22m/cap-alu-elec-polymer-22uf-35v/dp/68AC5722

vishay

https://www.newark.com/vishay/t55z107m016c0050/cap-100uf-16v-tant-polymer-case/dp/78AC7156?st=polymer%20capacitors

https://www.newark.com/vishay/mal218697554e3/cap-polymer-alu-elec-180uf-20v/dp/46AC9185?st=polymer%20capacitors