[R-390] 6080 in place of 6802 - RMS ???

[Roger L Ruszkowski]

Roger,
>snip<
>Your error above (and it's subtle if you
>read it quickly) is in thinking that power
>is proportional to voltage.  It's not, it's
>proportional to voltage squared.
Dave.
>snip<
--------------------------------------------------
Dave,

Power is voltage * (voltage / resistance)
Power is not voltage * voltage

Please stay with this use of band width here. This stuff is not easy or
it would be taught in the school house (it ain't so in all states).
And there are a lot of bad Urban Legends out there. Some
even apply to R390's
Try the following ideas on for size.

Bench test #1
Set your RS 12 volt 1 amp transformer (with a center tape secondary) up on
the lab bench.
Clip your single power diode to one 12 volt secondary lead
Clip your filter cap to the diode output and the other 12 volt secondary
lead.

The hand book says the secondary of the transformer will deliver 12 Watts
at 12 volts at 1 amp.
What value 12 watt load resistor should we apply to get a 12 watts of power
from the circuit to dissipate
as heat? (12 ohm)

The power dissipated as heat in a 12 ohm 12 watt resistor attached to the
circuit above is?
A.) None.
B.) 3 watts
C.) 6 watts
D.) 9 watts
E.) 12 watts

Bench test #2
If you reverse the diode and filter cap in the above circuit the power
dissipated as
heat in a 12 ohm 12 watt resistor attached to the circuit above is?
A.) None.
B.) 3 watts
C.) 6 watts
D.) 9 watts
E.) 12 watts

Bench test #3
Set your RS 12 volt 1 amp transformer (with a center tape secondary) up on
the lab bench.
Use the center tape on secondary as the common.
Clip your first single power diode to one 12 volt secondary lead
Clip your second single power diode to the other 12 volt secondary lead
Clip your filter cap to the diode outputs and the common point.

The hand book says the secondary of the transformer will deliver 12 Watts
at 12 volts at 1 amp.
What value 12 watt load resistor should we apply to get a 12 watts of power
from the circuit to dissipate
as heat? (12 ohm)

The power dissipated as heat in a 12 ohm 12 watt resistor attached to the
circuit above is?
A.) None.
B.) 3 watts
C.) 6 watts
D.) 9 watts
E.) 12 watts

Bench test #4
Set your RS 12 volt 1 amp transformer (with a center tape secondary) up on
the lab bench.
Clip your bridge rectifier  to the 12 volt secondary leads
Clip your filter cap to the bridge outputs.

The hand book says the secondary of the transformer will deliver 12 Watts
at 12 volts at 1 amp.
What value 12 watt load resistor should we apply to get a 12 watts of power
from the circuit to dissipate
as heat? (12 ohm)

The power dissipated as heat in a 12 ohm 12 watt resistor attached to the
circuit above is?
A.) None.
B.) 3 watts
C.) 6 watts
D.) 9 watts
E.) 12 watts


30|      |     | / Power Dissipated across filament load
28|      |     |/
26|______|_____|__All the voltage all the time_
24|......|..../|  All the power all the time
22|......|.../ |
20|......|../  |
18|......|./   |
16|      |/    |
14|______|_____|___All the voltage 1 / 2  time
12|     /|     |
10|    / | 1 /2 time voltage times 1 /2 time current is 1 /4 power
08|   /  |     |
06|  /   |     |
04| /    |     |
02|/_____|_____|________________________
00       |     | All the current all the time
-1       | All the current 1 / 2  the time
-2       |


With the 12 watt 12 volt 1 amp transformer,
a half wave 1 diode rectifier will yield 3 watts (6 volts .5 amps)
a full wave  2 diode rectifier will yield 6 watts (6 volts 1 amp)
a bridge 4 diode rectifier will yield 12 watts (12 volts 1 amp)

You stick 1 diode in a transformer secondary and hang any load on it you
want.
That transformer secondary is limiting the available power not the load.
At best you can have 1/4 of the power the transformer secondary will
deliver applied to the load.
If the load resistance is large enough to limit the power to less than the
transformer can
deliver then the power consumed in the load is less than the power that
could be consumed.

As soon a we install a diode in the 25.2 volt filament transformer line for
either the R390 series voltage regulators
of the PTO BFO filament , at best we limit the consumable power from that
transformer secondary to 1/4 of its
rated full power. Apply the wrong load and we get less power. Apply the
best optimum load and we get at best
1/4 of the power. The best load should be ratted to use 1/2 the volts and
1/2 the current.
For this two 6 volt filaments in series to form a 12 volt load.