Regulator for radio controlled model question

[Tristar500]

I've got a question about the Adjustable-Voltage Regulator LM317T or
similar.

I'm looking to build a small simple lightweight BEC (battery
elimination circuit)

I understand there are some advantages/disadvantages to using linear
regulators such as this as opposed to a switching power supply. The
switching power supply can cause RF noise but are generally more
efficient where as the liner don't cause any RF noise but can be
inefficient and create a lot of heat.

My question, If I'm using a LM317T or similar and am regulating the
voltage over a small range, lets say 9VDC volts down to 6VDC will the
efficiency be better with less heat if I was instead regulating the
range over a much broader spectrum say from 24VDC down to 6VDC?

I'd also assume that the heat and inefficiency goes up with the
current draw?

I suspect this to be true but I'm sure there are those of you out
there who would know for sure.

I'm looking for an output voltage of 4.5 to 6 VDC with a couple of
amps.

Thanks, Lawrence

 

[Dan Hollands]

Power is V x I

With a linear regulator the regulator acts like an adjustable resistor to
drop the unwanted voltage

if you go from 9V to 6V at 2A then the wasted power is 3V x 2A = 6Watts

if you go from 24V to 6V at 2A then the wasted power is 18V x 2A = 36Watts

A switching regulator gets rid of the extra voltage in a different way and
is therefore more efficient. It would probably be easier to design a 24 to
6V switching regulator than a 9 to 6V switching regulator but the design of
a reliable efficient switching regulator is not for the beginner.

Dan

--

Dan Hollands
1120 S Creek Dr
Webster NY 14580
585-872-2606
QuickScore@USSailing.net
www.QuickScoreRace.com


"Tristar500" <robot@innovationrobotics.com> wrote in message
news:1122735229.230942.199150@g44g2000cwa.googlegroups.com...

I've got a question about the Adjustable-Voltage Regulator LM317T or
similar.

I'm looking to build a small simple lightweight BEC (battery
elimination circuit)

I understand there are some advantages/disadvantages to using linear
regulators such as this as opposed to a switching power supply. The
switching power supply can cause RF noise but are generally more
efficient where as the liner don't cause any RF noise but can be
inefficient and create a lot of heat.

My question, If I'm using a LM317T or similar and am regulating the
voltage over a small range, lets say 9VDC volts down to 6VDC will the
efficiency be better with less heat if I was instead regulating the
range over a much broader spectrum say from 24VDC down to 6VDC?

I'd also assume that the heat and inefficiency goes up with the
current draw?

I suspect this to be true but I'm sure there are those of you out
there who would know for sure.

I'm looking for an output voltage of 4.5 to 6 VDC with a couple of
amps.

Thanks, Lawrence

 

[quietguy]

Have you had a look at the sites which have lots of circuits for RC
models? If not do a google search and you will be pleased - or make a
good start with...

http://www.speedy-bl.com/index.htm

David

Tristar500 wrote:

I've got a question about the Adjustable-Voltage Regulator LM317T or
similar.

I'm looking to build a small simple lightweight BEC (battery
elimination circuit)

I understand there are some advantages/disadvantages to using linear
regulators such as this as opposed to a switching power supply. The
switching power supply can cause RF noise but are generally more
efficient where as the liner don't cause any RF noise but can be
inefficient and create a lot of heat.

My question, If I'm using a LM317T or similar and am regulating the
voltage over a small range, lets say 9VDC volts down to 6VDC will the
efficiency be better with less heat if I was instead regulating the
range over a much broader spectrum say from 24VDC down to 6VDC?

I'd also assume that the heat and inefficiency goes up with the
current draw?

I suspect this to be true but I'm sure there are those of you out
there who would know for sure.

I'm looking for an output voltage of 4.5 to 6 VDC with a couple of
amps.

Thanks, Lawrence