[Boatanchors] Amp Supply LK500-ZC Amplifier Question

[WA5CAB--- via Boatanchors]

Sorry again, but again no.  It's only a matter of terminolgy but the DC 
value is the average, period.  

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480

In a message dated 08/02/2015 23:54:59 PM Central Daylight Time, 
jwiley at gci.net writes: 
> Au contraire, mon ami:    
> 
> While a DC voltage can vary in magnitude from a few microvolts or even 
> picovolts to many hundreds of kilovolts (or more), it is still DC.    Nowhere 
> does it say that a DC voltage has to remain constant in amplitude for it to 
> classified as DC.  Unless and until it reverses polarity, no matter how 
> briefly, or ceases to flow altogether,  it is still DC. 
> 
> - Jim, KL7CC
> 
>  
> 
> On 8/2/2015 8:29 PM, WA5CAB at cs.com wrote:
> 
> >> I'm sorry, but the phrase "DC Peak" is a contradiction in terms.  DC is 
>> forever.  Or at least many half cycles.
>> 
>> In a message dated 08/02/2015 23:11:31 PM Central Daylight Time, 
>> jwiley at gci.net writes: 
>> >>> 
>>> Actually, there is another way, and in my opinion, better: 
>>> 
>>> No filter capacitor at all, but instead 2 diodes, one connected as a 
>>> "half-wave" rectifier, in the normal manner, with  the other across the 
>>> relay coil, connected so as to absorb the "reverse EMF" generated by the 
>>> collapsing magnetic field.   
>>> 
>>> This configuration works because the current created by the collapsing 
>>> field, shunted through the diode across the field, maintains the field 
>>> until the next half cycle of the driving voltage arrives.  
>>> 
>>> Because the half-wave rectifier generates almost 18 volts of peak DC 
>>> from a 12.6 VAC source, or 28.3 volts DC peak from a 20 VAC source, either 
>>> should be enough to activate a 24-volt (nominal) DC relay.    
>>> 
>>> In a practical sense, it is helpful to remember that it takes much less 
>>> magnetic field strength to hold a relay closed than is required to 
>>> initiate closure. 
>>> 
>>> Also, the 2-diode configuration is much less expensive (parts wise) than 
>>> the diode plus electrolytic capacitor, and it  has the advantage of not 
>>> having to worry about the capacitor drying out at some future date.  
>>> 
>>> Parts budget:  2 diodes (1N4007) between 1.1 and 20 cents each, 
>>> depending on initial quantity purchased, vs, 1 diode plus one capacitor: 60 cents 
>>> to perhaps a dollar or more.   Since many hams find purchases of  1N4007 
>>> diodes in 1000 quantities (about $11 worth) makes sense, the 2-diode 
>>> approach becomes a more practical alternative. 
>>> 
>>> -  Jim, KL7CC
>> 
>