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ahgu
Joined: 19 Jun 2001
Posts: 170
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 24 Apr 2003 22:55 BJT or CMOS amplifier, lower noise? |
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I want to use either bjt or cmos to act as small preamp for an electret mic. in the ball park of gain of 10
probably use in common emitter configuration. Which one has lower noise?
and which part should I use for lower noise? part number?
thanks
Ahgu
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flatulent
Joined: 19 Jul 2002
Posts: 4856
Helped: 292
Location: Middle Earth
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| 25 Apr 2003 1:17 Try JFET |
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| Try a JFET. They have lower noise in the audio region than either MOS or BJT. The U301 or J301 will work well.
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arturt134
Joined: 01 Jan 1970
Posts: 140
Helped: 1
Location: Poland
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| 25 Apr 2003 6:39 |
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Please tell me who manufacture this amplifiers?
Thanks in advance.
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flatulent
Joined: 19 Jul 2002
Posts: 4856
Helped: 292
Location: Middle Earth
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| 25 Apr 2003 15:39 discrete transistors |
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| These are discrete transistors. Many companies make them.
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ahgu
Joined: 19 Jun 2001
Posts: 170
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| 26 Apr 2003 17:40 differential preamp with 2 jfets? |
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how can I make a diff jfet amplifier? want to min the noise.
using 2 jfets.
thanks
ahgu
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ahgu
Joined: 19 Jun 2001
Posts: 170
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| 26 Apr 2003 17:41 diff jfet amp |
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| with device matching , I wonder if it is actually better to use 2jfets, WRT just one jfet.
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flatulent
Joined: 19 Jul 2002
Posts: 4856
Helped: 292
Location: Middle Earth
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| 26 Apr 2003 19:33 doubled noise |
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| You will get double the noise. The topology is the same as BJT or MOS amplifiers.
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Borber
Joined: 01 Jan 1970
Posts: 1485
Helped: 111
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| 26 Apr 2003 20:13 bjt |
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Transistors BC550 NPN F=0.6dB at Ic=200uA Vce=5V f=15Hz-15kHz
BC560 PNP F=1dB
can be used.
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