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References: [ +from:dansawyer@earthlink.net: 117 ]

Total 117 documents matching your query.

101. [Amps] bipolar input and output impedance (score: 1): Author: Dan Sawyer <dansawyer@earthlink.net>; Date: Thu, 04 Jun 2009 07:35:21 -0700; What are the bipolar HF power transistor specs that influence or determine the input and output impedance? I have an ENI circuit using TH430 transistors with 4:1 input and output transformers, the EB; /archives//html/Amps/2009-06/msg00014.html (7,176 bytes)
102. [Amps] RF power transistor curve trace question (score: 1): Author: Dan Sawyer <dansawyer@earthlink.net>; Date: Sat, 13 Jun 2009 20:07:09 -0700; All, this is a continuing question in the quest to understand and modify an ENI base bipolar power amp. I speculated the power transistors were SD1728's however I am not so sure. I have one SD1728 fr; /archives//html/Amps/2009-06/msg00064.html (7,366 bytes)
103. Re: [Amps] RF power transistor curve trace question (score: 1): Author: Dan Sawyer <dansawyer@earthlink.net>; Date: Sun, 14 Jun 2009 19:02:38 -0700; Manfred, as always thank you for your response. Below are the answers: 1. the trace is a collector voltage horizontal and collector current vertical. The tracer is a Tek 577, the collector sweep is s; /archives//html/Amps/2009-06/msg00071.html (9,618 bytes)
104. Re: [Amps] RF power transistor curve trace question (score: 1): Author: Dan Sawyer <dansawyer@earthlink.net>; Date: Mon, 15 Jun 2009 19:46:45 -0700; Yes, a family of collector voltage and collector current curves. The step is the change in the base current. The tracer is not able to drive that much current, however it is able to drive one amp. At; /archives//html/Amps/2009-06/msg00074.html (10,533 bytes)
105. [Amps] amp update and question (score: 1): Author: Dan Sawyer <dansawyer@earthlink.net>; Date: Sun, 16 Aug 2009 19:17:03 -0700; The progress to 'adapt' an ENI amplifier to ham use is continuing, although suffering some from other summer activities. The current status is: 1. biasing is working, based on a simple resistor diode; /archives//html/Amps/2009-08/msg00339.html (7,322 bytes)
106. [Amps] source of '3rd harmonic' (score: 1): Author: Dan Sawyer <dansawyer@earthlink.net>; Date: Thu, 18 Nov 2010 21:31:53 -0800; All, I am trying to add bias to a commercial class B NPN RF module. The input and outputs are 4:1 and 1:4 'binocular' transformers, feedback is a simple CR network. The output has a significant 3rd h; /archives//html/Amps/2010-11/msg00340.html (6,822 bytes)
107. Re: [Amps] source of '3rd harmonic' (score: 1): Author: Dan Sawyer <dansawyer@earthlink.net>; Date: Fri, 19 Nov 2010 06:45:37 -0800; Ah, good question. The case is a simple single tone, x MHz in produces an amplified output of x MHz at plus some level and a series of odd harmonics, 3 times x. The 3rd harmonic is down 10 db from th; /archives//html/Amps/2010-11/msg00352.html (9,397 bytes)
108. [Amps] transistor matching question (score: 1): Author: Dan Sawyer <dansawyer@earthlink.net>; Date: Thu, 13 Jan 2011 06:54:26 -0800; Good morning, I am assembling and eb-104 amplifier board. A couple of questions: I have a set of MRF-150 devices to select the 4 required. Using a curve tracer I am able to find devices that have com; /archives//html/Amps/2011-01/msg00134.html (7,058 bytes)
109. [Amps] eb-104 bias question (score: 1): Author: Dan Sawyer <dansawyer@earthlink.net>; Date: Sun, 16 Jan 2011 13:17:03 -0800; All, I am building an eb-104. After several false starts, assembly errors, the board is up and running at low power with two devices. The current question is related to the bias circuit. I am using a; /archives//html/Amps/2011-01/msg00164.html (6,891 bytes)
110. Re: [Amps] eb-104 bias question (score: 1): Author: Dan Sawyer <dansawyer@earthlink.net>; Date: Sun, 16 Jan 2011 21:00:22 -0800; Thank you for all for your replies. They uncovered an interesting series of errors. I removed R6 and the result was the bias surged and wiped out a MOSFET - unambiguous 'white flash'. Whoops. The IC; /archives//html/Amps/2011-01/msg00167.html (10,413 bytes)
111. [Amps] switching mosfet rf amp - choice, schematic, and layout (score: 1): Author: Dan Sawyer <dansawyer@earthlink.net>; Date: Thu, 20 Jan 2011 20:57:21 -0800; All, I apologize for this request, it may be a bit like 'what is your favourite food'. It is not meant to be that wide open, here goes: I am interested in experimenting with fast switching mosfets wi; /archives//html/Amps/2011-01/msg00206.html (7,688 bytes)
112. [Amps] 'heat spreader' sizing ?? (score: 1): Author: Dan Sawyer <dansawyer@earthlink.net>; Date: Mon, 31 Jan 2011 18:42:42 -0800; The project is to mount a 1KW, 2 transistor, board on a heat sink. The transistor centers are about 2 inches. The question is: What should the dimensions of the heat spreader be? I have seen dimensio; /archives//html/Amps/2011-02/msg00005.html (7,047 bytes)
113. [Amps] how to recognize beryllium (score: 1): Author: Dan Sawyer <dansawyer@earthlink.net>; Date: Tue, 08 Feb 2011 19:55:00 -0800; All, how can beryllium be recognized? First: I know it is found in rf transistor tops; is it found in transistor mounts? An rf transistor mount has been scratched and needs to be resurfaced. The part; /archives//html/Amps/2011-02/msg00052.html (7,154 bytes)
114. [Amps] looking for a matched pair of MRF- 422 (score: 1): Author: dan <dansawyer@earthlink.net>; Date: Sat, 08 Jun 2013 13:09:53 -0700; I am looking for a matched pair of MRF-422. Does anyone have a set they are willing part with. Please send response to dansawyer at earthlink dot net Thanks, Dan, kb0qil _____________________________; /archives//html/Amps/2013-06/msg00186.html (6,713 bytes)
115. [Amps] matching power transistors. (score: 1): Author: dan <dansawyer@earthlink.net>; Date: Tue, 24 Dec 2013 05:43:42 -0800; Good day all. I am building an rf power amp from th430 / sd1728s. I have 6 devices and am looking for the best matched set. I also have a Tek curve tracer. I have set the tracer bias to produce the f; /archives//html/Amps/2013-12/msg00148.html (7,014 bytes)
116. [Amps] building an an758 questions (score: 1): Author: dan <dansawyer@earthlink.net>; Date: Wed, 05 Feb 2014 18:53:48 -0800; The project is building an an758. I am stuck on T1. How is T1 connected. The T1 included in the kit is small binocular style transformer with 'standard' pcb on the ends. The ends have common foil on; /archives//html/Amps/2014-02/msg00044.html (6,627 bytes)
117. [Amps] transistor mounting question (score: 1): Author: dan <dansawyer@earthlink.net>; Date: Fri, 07 Feb 2014 06:19:25 -0800; All, I am attempting to mount a new power module on an existing heat sink. The transistor mounting holes to not quite line up. Is it practical to machine the holes about 1/16 inch without destroying; /archives//html/Amps/2014-02/msg00053.html (6,634 bytes)

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