[Elecraft] how much current can the 5V Mic bias handle?

[Dr. Werner Furlan]

hi Stewart, 

On 8 Jan 2008 at 10:27, Stewart Baker wrote:

> Hi Werner,
> I would not recommend this approach.
> 
> The +5v from the Mic connector is for delivering a low current.
> It is susceptible to interference both in and out of the K2.
> 
> In addition any spiking on the +5V will effect the control board MCU
> due to poor design of it's reset circuitry. 
> 
> If you are happy making mods, then you can try this.
> 
> I put in a separate +5V supply to the Mic connector by using a 5V
> regulator mounted on the front panel board and fed from the 8A line on
> the RF board. There is a spare connector pin/socket (Pin 7 on J1) that
> is labeled AUXBUS(NC) which can be used to get the +8V thru. Of course
> the existing feed must be disconnected.
> 
> 73
> Stewart G3RXQ

thank you for your advice . 
I'll make a separate power supply. There is enough room for an 7805 
voltage regulator on the relais board I have added to switch the TrxPtc in my 
K2. This way I avoid any problem you have mentioned. 

73! de Werner
OE9FWV

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