Re: relays

On Fri, 14 Nov 2008 18:44:53 GMT, James Arthur
<bogusabdsqy@xxxxxxxxxxx> wrote:

John Fields wrote:
On Fri, 14 Nov 2008 07:18:13 -0800, John Larkin
<jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

On Fri, 14 Nov 2008 07:50:33 -0600, John Fields
<jfields@xxxxxxxxxxxxxxxxxxxxx> wrote:

On Thu, 13 Nov 2008 19:14:30 -0800, John Larkin
<jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

On Thu, 13 Nov 2008 13:22:44 -0600, John Fields
<jfields@xxxxxxxxxxxxxxxxxxxxx> wrote:

On Thu, 13 Nov 2008 08:34:58 -0800, John Larkin
<jjlarkin@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
Sure. And a latching relay has infinite gain.
---
Actually, it doesn't.

JF
OK, please post the equation for the power gain of a latching relay.
---
OK.

Pout
dB = 10 (log10) ------
Pin

Where Pout is the power dissipated in the load and the relay contacts,
Pin is the power needed to latch the contacts, and
dB is the power gain in decibels.

Clearly, no matter how minute the amount of power dissipated by the coil
while latching the relay, or how great the power dissipated by the load
and contacts after having been latched, unless Pin is zero the power
gain can never be infinite.

JF
You left out time.

---
Typical Larkinese subterfuge.

If you prefer,


Wout
dB = 10 (log10) ------
Win


Where the electrical energy W, in joules converted into heat in a
conductor of R ohms carrying a current of I amperes is I²Rt.

Which doesn't alter the fact that a latching relay doesn't have infinite
gain, that being the point of the article.

JF

The gain isn't infinite in that Win > 0, and Wout < infinity.

True, BUT, we being engineers, it's close enough.

Cheers,
James Arthur

I consider something that's unbounded to be infinite. What other
definition of "infinite" makes sense?

John

.

Relevant Pages

  • Re: relays
    ... it can't have infinite gain. ... please post the equation for the power gain of a latching relay." ... This more nearly describes the model you posit in that a certain charge, ...
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  • Re: relays
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  • Re: relays
    ... it can't have infinite gain. ... with a non-zero denominator you can't have an infinite quotient. ... please post the equation for the power gain of a latching relay." ...
    (sci.electronics.design)
  • Re: relays
    ... it can't have infinite gain. ... with a non-zero denominator you can't have an infinite quotient. ... please post the equation for the power gain of a latching relay." ...
    (sci.electronics.design)
  • Re: relays
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