testing capacitors orientation

[24 track]

I came across this video about testing for polarity of unmarked capacitors like orange drops , chicklets etc

I spent a good portion of today marking my stock for th e foil end of the cap this goes to the low inpedence side of the circuit , and as with almost every one else I believed that the black stripe marked on some caps indicated the foil side ........Not so mon ami , alot of time the caps are printed with out correct orientation . I was able today to test these with my oscilloscope as per the first video.




but there is an other lower tech way to test these as well using a guitar amp and a jumper cable, consisting of a1/4" plug and small piece of 2 conductor shielded wire with allegator clips in to each contact

heres a variation of that method , remember to always dischrge caps before testing as a rule of thumb



I'm looking at getting one of these for testing cap leakage ( Not physical leakage but D/C leakage ) in high voltage caps , this unit has 2 powersupplies in it , not only will it bring the cap upto current but will test the unit for D/C leakage

 

[24 track]

this cold be good also for testing the 200 + Nos caps i have as well

 

[rdjones]

Orange drops don't have "polarity".
Outside foil orientaion is a fully different concern than DC polarity.
If a film/foil or metalized film cap is installed "backwards" it will still be functional.
If an electrlytic is installed backwards it can explode when high voltage is applied.

 

[24 track]

Orange drops don't have "polarity".
Outside foil orientaion is a fully different concern than DC polarity.
If a film/foil or metalized film cap is installed "backwards" it will still be functional.
If an electrlytic is installed backwards it can explode when high voltage is applied.

of course that is explained in the first video , but if a Dipped cap is installed with the foil end to the high impedance side can , may ,and will induce hum to the circuit ,in an amp circuit, ( ya learn sumpin new evra day)

 

[Davecam48]

Unless something has drastically changed since I spent about 40 years repairing TV's Video's Audio equipment Hearing aids and just about all manner of electronic equipment, polyester capacitors have no polarity, electrolytic capacitors do and are ALWAYS marked as such!

DC

 

[24 track]

Unless something has drastically changed since I spent about 40 years repairing TV's Video's Audio equipment Hearing aids and just about all manner of electronic equipment, polyester capacitors have no polarity, electrolytic capacitors do and are ALWAYS marked as such!

DC

I thought so as well,
but the first video explains it in great detail and upto the mid 60's the foil end of caps were marked and even my mallory caps are still marked , but dipped caps like orange drops are not , and if installed backwards where the foil end is installed to the High impedence portion of the circuit act as an antenea of sorts , which may induce a noticeable hum into a circuit

with the dipped caps as they go down the line in manufacture are silk screened with the values , but the orientation may not be correct , and alot of my orange drops were the oposite to markings on the cap, watch the videos , it works .

 

[24 track]

this thread is just an FYI for those who can use the info, I wish i had been aware of this before , but now i know. and thats a good thing!

 

[kbold]

Unless something has drastically changed since I spent about 40 years repairing TV's Video's Audio equipment Hearing aids and just about all manner of electronic equipment, polyester capacitors have no polarity, electrolytic capacitors do and are ALWAYS marked as such!

DC

Perhaps shielding would have been a better term to use (or orientation for better shielding).

 

[24 track]

Perhaps shielding would have been a better term to use (or orientation for better shielding).

yes I agree, fixed!

 

[corliss1]

The outer foil stuff comes up all the time in guitar land, and it doesn't matter at the frequencies your amp is dealing with. If you're building a high frequency radio system, then it could be more critical.

 

[24 track]

The outer foil stuff comes up all the time in guitar land, and it doesn't matter at the frequencies your amp is dealing with. If you're building a high frequency radio system, then it could be more critical.

it could be a proximity issue with amps , but a reversed cap from a grid side to a plate side or foil end to the plate, high impedence side may be sensitive proximity to high voltage near by introducing a hum in the process. Foil side should always be orientated to lowest impedance end of the circuit.

 

[Renown]

The video was thoroughly boring. Maybe that's why I missed or slept thru that information in capacitor class however it was interesting and I learned something. I recapped a SUPRO but there's no way I'm going back to check or change polarity. I will say that the singlecoil pups in my tele cause a spurious noise ( big word). The humbuckers in the other geetar are noiseless. I wonder if it has something to do with the foil lead going to the hi impedance side. Or is it because single coil pups are just noisy.

Thanks for sharing that info. I need to go drink coffe now.

 

[24 track]

The video was thoroughly boring. Maybe that's why I missed or slept thru that information in capacitor class however it was interesting and I learned something. I recapped a SUPRO but there's no way I'm going back to check or change polarity. I will say that the singlecoil pups in my tele cause a spurious noise ( big word). The humbuckers in the other geetar are noiseless. I wonder if it has something to do with the foil lead going to the hi impedance side. Or is it because single coil pups are just noisy.

Thanks for sharing that info. I need to go drink coffe now.

glad you enjoyed your self

 

[NoTeleBob]

Forget polarity... I just want capacitors that have the tonz!

 

[24 track]

Forget polarity... I just want capacitors that have the tonz!

I built this for testing tone caps , the rotarty switch has 11 of the most common values in several differnt formats , ie , bumble bee, tropical fish, orange drop, oip, etc
plus you could test any cap you wished . the 2 push pull pots are rated for 250K and 500K . the A/B switch allows for acess to the both sides of the 11 position switch to test any cap plugged in. it works beautifully

my findings were that the value was relevant and the composition ,not so much , but that was just me

 

[Davecam48]

You certainly have spent some time on your test equipment.

DC

 

[Davecam48]

If it works for you it works I guess!

 

[Hamstein]

Many years ago, in the days when I had hair, and worked in electronics, I had a big can electrolytic explode in my face - I was leaning over it at the time and it splurged its guts out the top of the can, -it blew my fringe straight up and dyed it yellow!
It wasn't reversed, just faulty.

 

[24 track]

You certainly have spent some time on your test equipment.

DC

in the quest to learn all i am able to , i go a little etreme , after high school electronics ( I was in grade12 electronics while i was in grade 8 ) I have had no further training , some how i gained an intuition for repairs , so I study everything I can to answer the questions I have .

the box i built in post 15 was to answer a blind test for cap composition as this is a heated debate on most levels , also to be able to test veriable caps in guitar tone circuit to answer the question , What sounds best in my guitar ? and to lay to rest the composition debate for myself.

I like to engineer alot of my toys and build what ever i need.

 

[Renown]

I found this information useful as it could reduce microphonics? No?