D-104 Mike Info

[John Campbell]

Regarding the ptt switch on the D-104.....

Make sure that if you are switching an inductive load (relay coil) that
the load has a back-emf clamper diode across it. If not theres a pretty
good chance that the contacts will be zorched by the relay coil back emf
(considering the high operating voltage to begin with).

                     73......John (W8JNC)


>Date:         Sun, 10 Jan 1999 01:18:14 -0500
>Reply-To:     Multi-Volti Devices <multi-volti at SOFTHOUSE.COM>
>From:         Multi-Volti Devices <multi-volti at SOFTHOUSE.COM>
>Subject:      Re: D-104 Mike Info
>To:           HEATH at LISTSERV.TEMPE.GOV
>
>Yow! I hope someone confirms my gut reaction that that is the kind of
power
>you use a relay with big coin silver contacts to switch. maybe I'm
wrong,
>but I think the mike switch would weld. I think most keying circuits
are
>very low current. I would use an external relay or MOSFET switch,
>personally.
>
>Murray
>-----Original Message-----
>From: Keith Rowland <k4kgw at MINDSPRING.COM>
>To: HEATH at LISTSERV.TEMPE.GOV <HEATH at LISTSERV.TEMPE.GOV>
>Date: Saturday, January 09, 1999 7:01 PM
>Subject: D-104 Mike Info
>
>
>>Help!  Does anyone out there know how much voltage and current the PTT
>>switch in the older D-104 mikes will switch without self-destructing?
>>Will it do negative 120 VDC at about 300 ma.???
>>
>>Thanks,
>>
>>Keith
>>
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