ANTIQUE-RADIO-LAB

Antique Radio Forum for Collectors antique-radio-lab.forumotion.com
 
HomeHome  RegisterRegister  FAQFAQ  SearchSearch  Log inLog in  

Share | 
 

 Capacitor's (condensers), variable and fixed

View previous topic View next topic Go down 
AuthorMessage
Cliff Jones
Site Administrator
Site Administrator
avatar

Join date : 2010-11-22

PostSubject: Capacitor's (condensers), variable and fixed   2010-12-06, 11:12 pm

Questions and observations here

_________________
I'm a Science Thinker, Radio Tinkerer, and all around good guy. Just ask Me!
Back to top Go down
Guest
Guest



PostSubject: What capacitors to use?   2011-03-06, 12:06 pm

Hello all,
Fairly new to the old restorations. I am getting ready to order a supply of capacitors for the AA5 radios. I am not sure what is the best to
buy. I like the axial leads . What to buy.. Orange drop polypropylrene film......polyproplene metalized....and so forth.
I have looked at the Antique Radio Supply and Just Radios. Any other recommendations or suppliers. Also electrolytics styles and types.
Thanks for any help. Cliff
Back to top Go down
Cliff Jones
Site Administrator
Site Administrator
avatar

Join date : 2010-11-22

PostSubject: Re: Capacitor's (condensers), variable and fixed   2011-03-07, 4:33 pm

I think buying capacitors can be confusing. There are so many types to choose from. I recently bought a kit from just radios and was happy, now that I know, I have some to work with. However I didn't purchase any electrolytics, (which I am about to do.)

I don't think the orange drops are necessary, I think it may be just a oversell. Ordinary polypropylene caps should work, I have the axial leads with yellow bodies.

Although I am in the same boat. I will go for just radios electrolytic kit. I think its $59-$69. Then I am prepared. to start doing basic repairs. Others may have more experience than I, in the area of caps and I would like to get their opinions too.It is hard to know what and how many to have of each value, but a kit is a good starting point.

I just don't have time to do cost comparisons so I to have the same dilemma.

Heres a good info page on caps:
[You must be registered and logged in to see this link.]

Between you and I, we maybe, can make sense of the best types to get, and develop a users list of sellers and best buys. affraid Suspect Wink

PS: Welcome to our niche in the world wide web!

_________________
I'm a Science Thinker, Radio Tinkerer, and all around good guy. Just ask Me!
Back to top Go down
Cliff Jones
Site Administrator
Site Administrator
avatar

Join date : 2010-11-22

PostSubject: Re: Capacitor's (condensers), variable and fixed   2013-11-14, 2:38 pm

And heres a good refence in a PDF file:
[You must be registered and logged in to see this link.]

_________________
I'm a Science Thinker, Radio Tinkerer, and all around good guy. Just ask Me!
Back to top Go down
FrankB
Moderator
Moderator
avatar

Join date : 2010-11-22

PostSubject: Re: Capacitor's (condensers), variable and fixed   2014-04-24, 11:32 pm

Dont forget B&D Enterprises. [You must be registered and logged in to see this link.]
All top notch quality electrolytics and semi's.
Not the cheapo Chinese crap.
When I was in business I did 98% of my business with this folks. 100% guaranteed parts too.
Great kits of electro's and SMD's

If you don't know what kind of cap you need, they can find just what is needed. 105C caps too!
Back to top Go down
MEZLAW

avatar

Join date : 2012-10-28

PostSubject: Re: Capacitor's (condensers), variable and fixed   2014-08-29, 7:05 am

That is a great link Frank, thank you. Very Happy
Back to top Go down
Cliff Jones
Site Administrator
Site Administrator
avatar

Join date : 2010-11-22

PostSubject: Re: Capacitor's (condensers), variable and fixed   2015-04-23, 1:47 pm

I was browsing the web and found something worth remembering.

[You must be registered and logged in to see this image.]
This type of cap (polypropylene) is one that can replace the wax and paper caps without problems.
They are more temperature stable the disk caps.

They can be used In circuits, but they can cause problems if they are used incorrectly.

Here's the Problem. They have no mark on them to signify which lead is the outer foil.
Some paper caps and wax caps also have a ring around them one one end. That signifies the lead that should be used as a shield. This is normally chassis ground or negative side.


If it is used say,  in-between stages the non shielded lead should go to the lowest end-such as the grid of the next stage and the Shielded lead goes to the plate of the previous stage.

Here's why. stray magnetic and electrostatic fields.


Now you need to know which is which because there is no requirement for marking.

How can I  test ? you ask, why of course, and the answer is very simple.


Use your oscilloscope. Turn on your scope and set the highest sensitivity you can. take the probe lead and hold with your finger and thumb, at the lowest frequency you should see a non sinusoidal  trace pattern. this is power noise and you are infact acting as an antenna.

now put the ground lead of the probe to one of the leads and the probe lead to the other. Without touching either lead hold the body of the cap in your fingers. You should see some noise on the trace.

Now reverse the probe and ground leads and again hold the body of the cap with your fingers.

Notice any difference? You should!
The trace that is smaller indicates the lead that is the outer foil shield.

There you have it. Mark with a dot the shielded end on the body using a sharpie pen.

This will help in reducing Hum and extraneous noises into the circuit.

If any one sees that my explanation is incorrect please post a reply and I will square the info around to be correct.
That's my Hint on capacitors Idea

_________________
I'm a Science Thinker, Radio Tinkerer, and all around good guy. Just ask Me!
Back to top Go down
Cliff Jones
Site Administrator
Site Administrator
avatar

Join date : 2010-11-22

PostSubject: Re: Capacitor's (condensers), variable and fixed   2015-04-23, 2:00 pm

Another issue is trimmer caps.

[You must be registered and logged in to see this image.]

Make sure that the side with the screw is tied to the ground or chassis. The other side may be dangerous as there may be high voltage, upwards of several hundred volts DC. You need to use a metal screwdriver to turn these and make sure they have some heatshink sleeveing on the shaft so they won't short out against you or other components.

Do not!, however use a metal screwdriver on ferrite slugs as you will fracture or break the slugs and the metal will detune the coil.

Another Hint on Caps

_________________
I'm a Science Thinker, Radio Tinkerer, and all around good guy. Just ask Me!
Back to top Go down
FrankB
Moderator
Moderator
avatar

Join date : 2010-11-22

PostSubject: Re: Capacitor's (condensers), variable and fixed   2015-04-23, 7:14 pm

Great info on finding the outside foil! I would not have thought of that, but it makes perfect sense.

They also made the same style cap with color bands on it, just like the "bumble bee" types. Those threw me when I first saw them in a TV set. It was easy to figure out though, when I thought about it.

They also made disk ceramic caps with color dot coding. Pretty rare to find them, but they do exist.

When I first started I thought the tubular ceramics were actually resistors. A bit of research and I had that solved too.
Back to top Go down
 
Capacitor's (condensers), variable and fixed
View previous topic View next topic Back to top 
Page 1 of 1
 Similar topics
-
» Planet around cataclysmic variable QS Virginis?
» Fixed Eligibility Requirements for Alternative Methods of Procurement
» 12% fixed tax?
» waiting for your car to get fixed- full dream
» Resolution for Revaluation of Fixed Assets

Permissions in this forum:You cannot reply to topics in this forum
ANTIQUE-RADIO-LAB :: Radio Repair Bench :: Radio parts, Tools, and supplies. :: Capacitors-
Jump to: