Building a psu for linear amplifier
 

Hi

planning a power supply for NEC 36284 150W 2m linear amplifier with
2SC3286, see http://home.online.no/~la8ak/images/nec36284c.gif

It is only a simple psu, but using a 24VAC transformer
[http://home.online.no/~la8ak/images/4ua3.gif)

Wonder what size capacitors I should use to keep ripple minimum above
+24V?

73, Jan-Martin, LA8AK
http://home.online.no/~la8ak/c.htm
--
remove ,xnd to reply (Spam precaution!)

J M Noeding wrote:

Hi

planning a power supply for NEC 36284 150W 2m linear amplifier with
2SC3286, see http://home.online.no/~la8ak/images/nec36284c.gif

It is only a simple psu, but using a 24VAC transformer
[http://home.online.no/~la8ak/images/4ua3.gif)

Wonder what size capacitors I should use to keep ripple minimum above
+24V?

73, Jan-Martin, LA8AK
http://home.online.no/~la8ak/c.htm
--
remove ,xnd to reply (Spam precaution!)

I think this slide applies to 60 Hz power.
http://hyperphysics.phy-astr.gsu.edu...ic/rectct.html
--
John Popelish

J M Noeding wrote:

Hi

planning a power supply for NEC 36284 150W 2m linear amplifier with
2SC3286, see http://home.online.no/~la8ak/images/nec36284c.gif

It is only a simple psu, but using a 24VAC transformer
[http://home.online.no/~la8ak/images/4ua3.gif)

Wonder what size capacitors I should use to keep ripple minimum above
+24V?

73, Jan-Martin, LA8AK
http://home.online.no/~la8ak/c.htm
--
remove ,xnd to reply (Spam precaution!)

I think this slide applies to 60 Hz power.
http://hyperphysics.phy-astr.gsu.edu...ic/rectct.html
--
John Popelish

Ripple voltage across smoothing capacitors can be calculated from the amount
by which they discharge, at the DC load current, during the time of a
half-cycle of the power supply frequency.

For half-wave rectification, ie., a single diode plus capacitor, the
capacitors are charged up once per cycle and the capacitor discharges into
the DC load during the period of a whole AC cycle.

---------------------------

Ripple voltage across smoothing capacitors can be calculated from the amount
by which they discharge, at the DC load current, during the time of a
half-cycle of the power supply frequency.

For half-wave rectification, ie., a single diode plus capacitor, the
capacitors are charged up once per cycle and the capacitor discharges into
the DC load during the period of a whole AC cycle.

---------------------------

On Sun, 30 Nov 2003 02:19:14 GMT, John Popelish
wrote:


planning a power supply for NEC 36284 150W 2m linear amplifier with
2SC3286, see http://home.online.no/~la8ak/images/nec36284c.gif

It is only a simple psu, but using a 24VAC transformer
[http://home.online.no/~la8ak/images/4ua3.gif)

Wonder what size capacitors I should use to keep ripple minimum above
+24V?

73, Jan-Martin, LA8AK
http://home.online.no/~la8ak/c.htm
--
remove ,xnd to reply (Spam precaution!)

I think this slide applies to 60 Hz power.
http://hyperphysics.phy-astr.gsu.edu...ic/rectct.html
--
John Popelish

thanks,
very basic, but it may be a good reply, and as quoted "They can be
modified to 50 Hz by examination of the expressions."

suppose R = U/I for this expression?

Jan-Martin
--
remove ,xnd to reply (Spam precaution!)

On Sun, 30 Nov 2003 02:19:14 GMT, John Popelish
wrote:


planning a power supply for NEC 36284 150W 2m linear amplifier with
2SC3286, see http://home.online.no/~la8ak/images/nec36284c.gif

It is only a simple psu, but using a 24VAC transformer
[http://home.online.no/~la8ak/images/4ua3.gif)

Wonder what size capacitors I should use to keep ripple minimum above
+24V?

73, Jan-Martin, LA8AK
http://home.online.no/~la8ak/c.htm
--
remove ,xnd to reply (Spam precaution!)

I think this slide applies to 60 Hz power.
http://hyperphysics.phy-astr.gsu.edu...ic/rectct.html
--
John Popelish

thanks,
very basic, but it may be a good reply, and as quoted "They can be
modified to 50 Hz by examination of the expressions."

suppose R = U/I for this expression?

Jan-Martin
--
remove ,xnd to reply (Spam precaution!)

It is only a simple psu, but using a 24VAC transformer
[http://home.online.no/~la8ak/images/4ua3.gif)

Wonder what size capacitors I should use to keep ripple minimum above
+24V?
=====
As a rule of thumb not less than 2000 microFarad per ampere
Hence for a 20 Amperes supply a total of 40KmicroFarad or more.

Frank GM0CSZ / KN6WH

It is only a simple psu, but using a 24VAC transformer
[http://home.online.no/~la8ak/images/4ua3.gif)

Wonder what size capacitors I should use to keep ripple minimum above
+24V?
=====
As a rule of thumb not less than 2000 microFarad per ampere
Hence for a 20 Amperes supply a total of 40KmicroFarad or more.

Frank GM0CSZ / KN6WH

J M Noeding wrote:
Hi

planning a power supply for NEC 36284 150W 2m linear amplifier with
2SC3286, see http://home.online.no/~la8ak/images/nec36284c.gif

It is only a simple psu, but using a 24VAC transformer
[http://home.online.no/~la8ak/images/4ua3.gif)

Wonder what size capacitors I should use to keep ripple minimum above
+24V?

Work it out for sure, using Duncan Munro's PSU Designer program. Follow
the link from the 'In Practice' pages:
http://www.ifwtech.co.uk/g3sek/in-prac/best-of.htm#psud


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek