Robert Rolf 10:46 2005-12-13:

>Morgan Olsson wrote:
>>Dmitriy Kiryashov 06:08 2005-12-13:
>>
>>>Question 2 All: How someone would mute the circuit without causing pop=
s ?
>>
>>1) PWM ramp at insanely high PWM frequency?

I saw you have the same idea :)

>>(but that would also load the signal source much if the output switches=
 between input and GND)
>>2) Use OPTO-fet from source to output, driven by PWM+RC.  Pull output t=
o GND with a stndard switch IC/transistor whatever only when totally OFF.
>>3) motor + pot.... ;)
>>Actually i have read about chips that have pop free muting don=B4t reme=
mber where, look at Linear tech or Maxim...
>
>They use the zero crossing to gate the switch on/off.

I have seen simple LED+FET devices made specifically for soft switching.

(And also seen an old design using lamp + VDR.)

/Morgan
--
Morgan Olsson, Kivik, Sweden


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