24 Volt DC to 5 Volt DC - need help constructing a simple circuit

[[email protected]]

It's been a few years since I had an electronics course, so I need help
with a relatively easy question.

I need to reduce 24 volts DC to 5 volts DC. I think it's just a matter
of a couple resistors but am unsure. The amperage is relatively low
(not sure exactly).

Can anyone help? Details would be much appreciated.

Thanks,
-Dan

 

[Ignoramus17480]

It's been a few years since I had an electronics course, so I need help
with a relatively easy question.

I need to reduce 24 volts DC to 5 volts DC. I think it's just a matter
of a couple resistors but am unsure. The amperage is relatively low
(not sure exactly).

Can anyone help? Details would be much appreciated.

Look up a voltage divider circuit. It is made with a couple of
resistors


+24V ---------------------------
|
<

R1

|-------------- +5V
<

R2

|
0 -------------------------------------------- 0

i

 

[John B]

It's been a few years since I had an electronics course, so I need
help with a relatively easy question.

I need to reduce 24 volts DC to 5 volts DC. I think it's just a
matter of a couple resistors but am unsure. The amperage is
relatively low (not sure exactly).

Can anyone help? Details would be much appreciated.

Thanks,
-Dan

7805L regulator. Costs about 50 cents and comes in TO92 package.

 

[Dope mcSmoke]

7805L regulator. Costs about 50 cents and comes in TO92 package.

But it might get hot fed with 24V

 

[John B]

But it might get hot fed with 24V

Yes it might, that depends on the current consumption. But it won't get
any hotter than the dropper resistor in a potential divider and the
output will more stable.

If in doubt use a standard 7805 1A regulator bolted to Mr mcSmoke's
dope tin.

 

[Fred Bloggs]

It's been a few years since I had an electronics course, so I need help

with a relatively easy question.

I need to reduce 24 volts DC to 5 volts DC. I think it's just a matter
of a couple resistors but am unsure. The amperage is relatively low
(not sure exactly).

Can anyone help? Details would be much appreciated.

Yeah - details are what's needed- the "amperage" is all important so why
don't you find out what it is before your ask your dumb question.

 

[Don Foreman]

Yes it might, that depends on the current consumption. But it won't get
any hotter than the dropper resistor in a potential divider and the
output will more stable.

If in doubt use a standard 7805 1A regulator bolted to Mr mcSmoke's
dope tin.

If you're talking about more than 100 mA, consider a Simple Switcher
from National Semiconductor. Check out LM2678-5.0. It won't need
a heatsink for currents up to 2 amps or more. The website "web
bench" will design the circuit for you, including giving you a parts
list.

http://www.national.com/appinfo/power/webench/

 

[[email protected]]

Yeah - details are what's needed- the "amperage" is all important so why
don't you find out what it is before your ask your dumb question.

Ooohh such anger, now I know who the '40 Year Old Virgin' was based on.

 

[ehsjr]

Ooohh such anger, now I know who the '40 Year Old Virgin' was based on.

Fred Bloggs contributes wonderful circuits here. You would be
very hard pressed to get better help than he can provide - if
that is possible. You mistake accuracy as anger.

Ed

 

[Peter Bennett]

Ooohh such anger, now I know who the '40 Year Old Virgin' was based on.

Fred's response may be a bit blunt, but we do need to know the load
you want to run from the 5 volts. If the current is very low and
stable, a resistive divider may do, but if the load varies a lot, a
regulator would be necessary.