# amperage multiplier

Discussion in 'Misc Electronics' started by Camilo Andres Gil Cardona, Nov 19, 2003.

1. ### Camilo Andres Gil CardonaGuest

Hi everybody! i need to know how to multiply current, but true
multiplying, not amplification with transistors or something like
that. What methods there are for that?! (i want something like the
current amplification of a transformator when relationship of wires is
established for current multiplication, real multiplication)

2. ### Robert MonsenGuest

If you use a 1 ohm sense resistor, measured voltage across the resistor
equals current. Or, if you need isolation, use a current transformer.

Then, you use a voltage multiplier chip, like an AD633 to get the result as
a voltage.

You can change this back to a current if you want by using a simple opamp
circuit as follows:

VCC
+
|
+-------+
| |
| .-.
| | |
| '-'
| |
| |
|\| ||-+
+---|-\ ||<- N channel MOSFET
From MPY | | >---||-+
----------|+/ |
| |/| |
| | |
| | |
+-----|-------+
| .-.
| | |
| | | 1 ohm
| '-'
| |
+-------+
===
GND
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

Use a rail to rail opamp.

Regards,
Bob Monsen

3. ### Bob F.Guest

Was this AC or DC? Why can't you use transistors. Transformers (not
"transformators") transform an AC signal from one amplitude to another
amplitude. For example 120vac is transformed into 12vac in your video tape
recorder with a transformer. Current multiplication is really current
amplification, really. If you want more current, you need to design (or
purchase) a larger capacity power supply. If you want a serious answer to
do.

4. ### Mark FergersonGuest

Here's a weird circuit I ran across that was designed for
use with HV AC supplies like Tesla coils. It looks like a
sorta inverse of the familiar voltage multipler circuits
that use diodes and caps.

+out
o
|
_V_
________________|______________
| | | |
L L L L
| | | |
ACin o->|--||--->|--||---->|---||--->|---||---->|--o ACin
| | | |
L L L L
|________|_________|_________|
|
_V_
|
o
-out

The "_V_"s and "->|-"s represent diodes (select for
appropriate V & I characteristics), the "-||-"s are
capacitors, and the Ls are fat iron-cored inductors.

(You hafta kinda squish the diagram vertically to see
that the Ls connect between the diodes and caps.)

I have not built this, so let us know how (if) it works, OK?

Mark L. Fergerson