EMRFD Message Archive 4506

Message	Date	From	Subject
4506	2010-04-05 08:15:39	alan7114p	Capacitor value in Regenerative Receiver
I am trying to build the Regenerative Receiver that starts on P 1.9 in EMRFD, 3rd edition. The schematic shows a polarized capacitor attached to the collector of Q3. The value given is '5u'. That does not appear to be a standard value. Does anyone know if this is correct? If so, does 4.7uF seem reasonable? 73 de Alan K6ZY
4507	2010-04-05 08:34:29	Leon Heller	Re: Capacitor value in Regenerative Receiver
On 05/04/2010 16:14, alan7114p wrote: > I am trying to build the Regenerative Receiver that starts on P 1.9 in EMRFD, 3rd edition. The schematic shows a polarized capacitor attached to the collector of Q3. The value given is '5u'. That does not appear to be a standard value. Does anyone know if this is correct? If so, does 4.7uF seem reasonable? It won't make any difference. Electrolytics typically have very wide tolerances (25% or so), and it's only an audio coupling capacitor. I can't see why they chose 5 uF. 73, Leon -- Leon Heller G1HSM
4508	2010-04-05 09:17:53	Michael Clarke	Re: Capacitor value in Regenerative Receiver
Choice of 5uF might be something to do with simple audio filtering. Regens can squeek a lot! 73 Michael Mi5mtc
4509	2010-04-05 09:31:18	Leon Heller	Re: Capacitor value in Regenerative Receiver
4510	2010-04-05 10:03:22	ajparent1	Re: Capacitor value in Regenerative Receiver
4511	2010-04-05 11:21:01	Alan Whitman	Re: Capacitor value in Regenerative Receiver
Thanks to all for the quick responses! I suspected that there would be quite a bit of latitude in the value to use here. I particularly appreciate Allison's explanation as to what the cap is there for. I will use a 4.7uF, as I have several available. As always, this group is extremely helpful. 73 de Alan K6ZY [Non-text portions of this message have been removed]
4539	2010-04-21 06:04:21	Tim	Part values (was Re: Capacitor value in Regenerative Receiver)
4541	2010-04-21 06:50:52	John Levreault	Re: Part values (was Re: Capacitor value in Regenerative Receiver)
Tim wrote: > At the other end of the extreme, I have actually met young electronic desginers who don't understand my natural gravitation towards "handy dandy" values like 1K and 3.3K and 4.7K which date from the old 20% tolerance E6 series. They don't see any reason for those values, because as far as they can tell 1% resistors in the E96 series are to be chosen. Weird for me to see someone spec a resistor to 3 decimal places to light a LED, but that's how they think! > It's also related to what they can actually buy. I've frequently had problems finding E24/5% resistors, but rarely if ever a problem finding E96/1%'ers. And the price difference is virtually insignificant. I gave up using 5% values years ago, but I like to use, say, 1.00K, 3.32K, 4.75K, etc., i.e. close to the E24 values. Certainly makes me feel better. John NB1I