Elenco Electronics MO-1251 Manual do Utilizador descarregar pdf (Página 25)

A &

A Engineering

2521 W.

LaPalma Unit

K

Anaheim, CA

92801

(714)

952

-2114

BLH Electronics

75 Shawmut

Road

Canton,

MA 02021

(617) 821

-2000

Colorease

100 E. Ohio Street

Chicago,

IL 80611

(312)

440 -1266

Electronic

News

7 East

12th

Street

New

York, NY

10003

(215) 630 -0951

Gould

/AMI

1200 Buckskin

Road

Pocatello,

ID 83201

(800)

468-5310

ID Systems

174 Concord

Street

Peterborough,

NH 03458

(603)

924

-9631

NAMES AND NUMBERS

Lazer

Products

12741 E. Caley

Avenue

no.

130

Englewood,

CO

80111

(303)

792-5277

Maxim

120 San Gabriel

Drive

Sunnyvale,

CA 94086

(408)

737 -7600

Mitel

2321

Morena

Blvd, Suite

M

San

Diego, CA

92110

(619)

276 -3421

Nuts &

Volts

PO

Box

1111

Placentia,

CA 92670

(714) 632

-7721

Old Colony

Sound

Lab

PO Box

243

Peterborough,

NH 03458

(603) 924

-6371

Rohm &

Haas

Box

219

Bristol,

PA

19007

(215)

788 -5501

Sensors

174 Concord

Street

Peterborough,

NH 03458

(603)

924-9631

Sharp

Sharp

Plaza

Mahwah,

NJ 07430

(201) 529

-8757

Stanford

Telecomm

2421

Mission

College

Blvd

Santa

Clara,

CA

95054

(408) 748 -1010

Tek Direct/Tektronix

PO

Box 500

M/S 02

-050

Beaverton,

OR 97075

(800)

426 -2200

Texas

Instruments

Box 655303

M/S 8206

Dallas,

TX 75265

(214)

995 -3821

Whole

Earth

Access

2990

Seventh

Street

Berkeley,

CA

94710

(800)

845 -2000

News. You'll

find lots of

free

-sam-

ple,

offers

in any of

those, along

with

unique

sources

of supply.

As

usual,

you get a complete

list from

Uhlrichts

Periodicals

Dictionary at

your

local

library.

(11) Acquire an enormous

junk

box. Or better

yet, a junk

room or

a junk

building or

two.

Fill them

with broken

TV sets, dead

VCR's,

or

whatever else

trips your

trigger.

A

dozen cubic

yards or

so should

do

for a bare -bones

start.

(12) Hamfests,

particularly

the

big

regional ones,

have outstand-

ing

parts

bargains

and

zero

mini-

mum orders.

Ask for

full

details

at

your

local ham club,

or, once

again,

do see

Nuts and

Volts

for a

listing.

(13) Combine your

order

with

that of

another

hardware

hacker.

Or

start your

own

"buying club."

Low

-power regulators

The

folks at

Maxim have

added

yet

two more

low -power

regulator

chips to their

line. The

MAX644

steps

up a single

alkaline

cell

as

weak as 0.9

volts

up to a

fixed and

regulated 5.0

volts.

The

MAX645

gives the same

treatment

to a

2.4-

volt lithium cell.

Figure

2 shows you

the circuit.

The

secret

is

to

have two

switching

regulators.

The first

regulator

gen-

1.5

volt

alkaline "D" cell

4.7

mHy

100

µHy___

0000

recommended

inductors

are Caddell

-Burns

parts

#1730

-45

and #7070 -25

0000000

nc n

22

µF 0.001

µF

1N5817

220

µF

+5

VDC

output

FIG. 2 -THIS

SIMPLE

SWITCHING

REGULATOR steps

up a single

alkaline cell

to give you

a fixed

+

5 -volt

output at 50

milliamps.

An external

pass transistor

can be added

for

more

output

current.

erates

around

12 volts or so at a

very low current

for

internal use.

That high

voltage

gives

enough

MOS transistor

base drive to

allow

for

high

efficiency.

While the circuit

is quite simple,

careful

selection of

the

inductors

and the

Schottky diode

are

needed

for maximum efficiency.

The

typical efficiency

is

in the

75- percent

range. Currents

up to

59

mils are directly

available,

while

an external

pass transistor

may be

added

for higher current

needs.

For this month's contest,

just

tell

me what you

would do

with a

micro -power

regulator that deliv-

ers

+5 volts off a

nearly dead

sin-

gle alkaline cell.

We

will have all

the usual

Incredible Secret

Money

Machine book

prizes, along

with

an all-

expense -paid

(FOB

Thatcher, AZ) tinaja

quest

for two

for the best entry

of all.

Send all

your

written entries to

me and

not

to

Radio -Electronics.

Refilling SX cartridges

As we have seen

in past col-

umns, a profitable

business

can be

built up

centered around

refilling

toner cartridges

for copiers

and

laser printers.

Many recent

hacker

helpline

requests

have been

for

methods to

refill those Canon

SX

cartridges as

used

in

the

LaserJet

11

and the

LaserWriter

II.

27

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