[GreenKeys] Solid State relays

[Paul Kasley]

Your ohmmeter is probably sourcing the gate drive current thru the internal 
diode bridge thru the internal optocoupler to the internal SCR.  SCRs and 
triacs have a minimum hold current and the 60mA may not be sufficient. There 
are DC rated SSRs that use MOSFETs instead of SCRs. I'm not sure if you can 
find an optocoupler with a 300V VCEO transistor output that can pound 60mA 
directly. Also, you need to snub the coils to manage the inductive kick when 
the transistor turns off - a simple 1N4004/5/6 diode may do the trick 
without excessively lengthening the current pulses thru the coils.

-w9ts

----- Original Message ----- 
From: "Larry Tighe" <larryradio at att.net>
To: <hunybuny at eskimo.com>
Cc: <greenkeys at mailman.qth.net>
Sent: Wednesday, August 25, 2010 1:50 PM
Subject: Re: [GreenKeys] Solid State relays


> Yes but.....the ohmmeter is very low voltage DC and responds to the
> closures...in either polarity direction !
>
> lar
> ----- Original Message ----- 
> From: <hunybuny at eskimo.com>
> To: "Larry Tighe" <larryradio at att.net>
> Cc: <greenkeys at mailman.qth.net>
> Sent: Wednesday, August 25, 2010 2:35 PM
> Subject: Re: [GreenKeys] Solid State relays
>
>
>> Hey Larry;
>>
>> I'd guess because it is a SOLID-STATE relay and is expecting AC not DC.
>>
>> I can't remember what that "transistor" is called, but it can handle
>> some serious VAC, but doesn't work with DC.
>>
>> UE,
>> W6ESE - tony
>> NNNNZCZC
>
> ______________________________________________________________
> GreenKeys mailing list
> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:GreenKeys at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>