Hi all fellow techs!!

I wonder what they put in those very small devices.It is certainly not
a real power transformer. Low power devices (50W) contain an
autotransformer.(I took one apart)

I think it might be some kind of dimmer (good only for resistive
loads).
Has anyone taken one of those gadgets apart??

Many thanks for your feedback.

Jacques

It is either a circuit very similar to a light dimmer, or possibly just a
rectifier.

"Jacques Carrier" wrote in message
om...
Hi all fellow techs!!

I wonder what they put in those very small devices.It is certainly not
a real power transformer. Low power devices (50W) contain an
autotransformer.(I took one apart)

I think it might be some kind of dimmer (good only for resistive
loads).
Has anyone taken one of those gadgets apart??

Many thanks for your feedback.

Jacques

"Michael A. Covington" writes:

It is either a circuit very similar to a light dimmer, or possibly just a
rectifier.

A rectifier would cut the power in half compared to 230 VAC for a constant
resistive load. This is not what you want.

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"Sam Goldwasser" wrote in message
...
"Michael A. Covington" writes:

It is either a circuit very similar to a light dimmer, or possibly just
a
rectifier.

A rectifier would cut the power in half compared to 230 VAC for a constant
resistive load. This is not what you want.

I thought the high powered ones were nothing but diodes? They're only good
for resistive loads, mostly they're made for irons and hair dryers.

"James Sweet" writes:

"Sam Goldwasser" wrote in message
...
"Michael A. Covington" writes:

It is either a circuit very similar to a light dimmer, or possibly just
a
rectifier.

A rectifier would cut the power in half compared to 230 VAC for a constant
resistive load. This is not what you want.

I thought the high powered ones were nothing but diodes? They're only good
for resistive loads, mostly they're made for irons and hair dryers.

A diode would produce half wave rectified 230 V. This would cut
the power in half compared to using raw 230 VAC but would still
be twice the power expected by a 115 VAC resistive load.

For example: 115 VAC 1.5 kW space heater.

On 230 VAC: 6 kW.
On half wave rectified 230 VAC: 3 kW.

Either would result in failure very quickly.

Or, did you have something else in mind?

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header is ignored.
To contact me, please use the feedback form on the S.E.R FAQ Web sites.

"Sam Goldwasser" wrote in message
...
"James Sweet" writes:

"Sam Goldwasser" wrote in message
...
"Michael A. Covington" writes:

It is either a circuit very similar to a light dimmer, or possibly
just
a
rectifier.

A rectifier would cut the power in half compared to 230 VAC for a
constant
resistive load. This is not what you want.

I thought the high powered ones were nothing but diodes? They're only
good
for resistive loads, mostly they're made for irons and hair dryers.

A diode would produce half wave rectified 230 V. This would cut
the power in half compared to using raw 230 VAC but would still
be twice the power expected by a 115 VAC resistive load.

For example: 115 VAC 1.5 kW space heater.

On 230 VAC: 6 kW.
On half wave rectified 230 VAC: 3 kW.

Either would result in failure very quickly.

Or, did you have something else in mind?

I was thinking they had a chain of diodes and made use of the voltage drop,
guess I could be wrong though.