Antique Radios Forum

This is the temporary home of the Antique Radio Forums while a new server to host it is being found. You will have to register here to post. Please Note: None of these topics will be preserved when the original forums are back.
 
HomeCalendarFAQSearchMemberlistUsergroupsRegisterLog in

Share | 
 

 A question about L|C and R|C and (L-R)|C circuits

View previous topic View next topic Go down 
AuthorMessage
keeperofthegood



Posts : 21
Join date : 2010-10-12

PostSubject: A question about L|C and R|C and (L-R)|C circuits   Mon Oct 18, 2010 11:38 am

Hey oh

Ok, I never know the difference between RC and LC in terms of oscillation function. What I know is that I need a DC resistive component around 1meg, but I need an oscillation around 30kc (super sonic chopper, can range 20kc and up so not a critical value)

So, would a 1meg in series with a 1mH coil, with a 22nF capacitor parallel to that combination suit or am I making life too complicated?


Thanks Very Happy

Back to top Go down
View user profile
dberman51



Posts : 19
Join date : 2010-10-13

PostSubject: Re: A question about L|C and R|C and (L-R)|C circuits   Mon Oct 18, 2010 11:44 am

Ummm, I think you need to consider the type of oscillator circuit you will be using. Hartley? Wien bridge? Colpitts?

-David
Back to top Go down
View user profile
keeperofthegood



Posts : 21
Join date : 2010-10-12

PostSubject: Re: A question about L|C and R|C and (L-R)|C circuits   Mon Oct 18, 2010 11:51 am

Simple grid leak. Nothing more complicated than that, other than knowing I need the R for loading but I need to know a time base and RC's are filters and not oscillator pairs and an LC of 22nF and 1mH will give me a resonance of around 30kc.
Back to top Go down
View user profile
pixellany



Posts : 58
Join date : 2010-10-12

PostSubject: Re: A question about L|C and R|C and (L-R)|C circuits   Mon Oct 18, 2010 6:12 pm

Is a "grid-leak" oscillator the same as "electron-coupled"?

Regardless, please post a schematic of the circuit you have in mind.

does it need to be tunable?
Back to top Go down
View user profile
keeperofthegood



Posts : 21
Join date : 2010-10-12

PostSubject: Re: A question about L|C and R|C and (L-R)|C circuits   Mon Oct 18, 2010 6:20 pm

Here we go:




The R|C forms a chopper oscillator typically 20kc and higher. Bad circuit but minimal parts used and is supposed to be fairly sensitive; bad because it can radiate as well as receive. However, I have some 4AH5's from Jim and figured I had not a lot else to do today so I got putting parts together to give it a go, but got to wondering about the oscillator idea. What values for R and C would I need? And L and C is easy enough, when it is an R|C it is a filter not an oscillator and I have not seen a resonance formula for that. Etc etc etc etc of course, and so posted the thoughtful musing about this.
Back to top Go down
View user profile
Alan Douglas



Posts : 62
Join date : 2010-10-13

PostSubject: Re: A question about L|C and R|C and (L-R)|C circuits   Mon Oct 18, 2010 7:14 pm

It may depend on the tube characteristics more than the external circuit. I guess you could look up blocking oscillators but this circuit looks like cut-and-try.
Back to top Go down
View user profile
keeperofthegood



Posts : 21
Join date : 2010-10-12

PostSubject: Re: A question about L|C and R|C and (L-R)|C circuits   Mon Oct 18, 2010 8:06 pm

Laughing I agree with that Alan. I am just wondering how putting a 1meg in series with a 1mh would affect the R|C characteristics.

Otherwise, the school text this is from only "introduces" this circuit and does not go into any detail on its construction so yes, guesswork ahead of me Question
Back to top Go down
View user profile
Sponsored content




PostSubject: Re: A question about L|C and R|C and (L-R)|C circuits   

Back to top Go down
 
A question about L|C and R|C and (L-R)|C circuits
View previous topic View next topic Back to top 
Page 1 of 1
 Similar topics
-
» power weapon question
» dedicated transport question
» Transportation question
» A possibly stupid and stereotypical question
» Question about Unholy Caster Paly

Permissions in this forum:You cannot reply to topics in this forum
Antique Radios Forum :: Antique Radio Forums :: Electrical/Mechanical Restoration-
Jump to: