Silicon Valley Computer SHUGART 706 User Manual download pdf (Page 13)

LETTERS

COMPONENT NUMBERING

SYSTEMS

I enjoy reading your

depart-

ment, "Antique Radios." It's

brought

back

memories

of our

first Atwater -Kent,

and how I first

began in radio around 1938.

Some of the history

of those

days is, I fear,

becoming lost. One

of the things that distresses me is

when I hear

someone refer to

a

diode, such as a 1N914

as an

"eye

-

en" 914.

Did

you

know

that the

XN (1N,

2N,

3N, 4N)

system of numbering

semiconductor devices

was

actu-

ally

invented

before there

were

transistors? Before there were

transistors (prior to 1948) there

were tubes

and

solid

-state "crys-

tal"

diodes.

During World War Il

solid -state diodes, the venerable

1N21, IN23, IN23A, and 1N23B

among them, were

used

as mixers

in radar receivers. Their function

was to

downconvert the

incoming

RF

energy so that

it

could be ampli-

fied at

a

lower frequency.

The tube

-numbering

system

most in favor

at

the time was

of

the

::;t31

It:.«rt

nXRt

t,t.r.xod

.7!/I!Kt'.VS:r

LETTERS

RAD

/O-

ELECTRON

/CS

500

-49

B

/-

COUNTY BOULEVARD

FARM

/NGDALE, N Y 1/735

form

nXn; for

example a 6L6. The

first number indicated

the nomi-

nal filament

or heater voltage. The

letter indicated

whether

the de-

vice

was an amplifier

or a rectifier.

Letter

designations in

the first half

of

the

alphabet were amplifiers;

letter

designation in

the second

half

of the alphabet were rectifiers.

(From that, we

see that the L in

the

tube number

indicated that

the

6L6 was

an amplifier.) The final

number

indicated

the number of

active electrodes.

With

CRT's, the first number in-

IPL,.IPL"

6

a''0

a`

1=

----- . _

7:1E:773.7.

.

HM 205

-2

the

new Digital

Storage

Oscilloscope

with 5 MHz sampling

rate

and 2

x 1024

/ 8 bit storage

realtime bandwidth DC

-20

MHz $

888.00

HM 8148

the

new

intelligent Graphic

Printer

firmware for

time, date,

interval, linear interpolation

zooming

function $788.00

DSO Software

with 13

programs

incl. IEEE BUS card

$480.00

call toll

free

(800) 247-1241

HAMEG,

Inc.

88 -90 Harbor Road - Port Washington, N.Y.

11050

Phone

(516) 883 -3837

Telex (023) 497.4606

CIRCLE

62 ON FREE INFORMATION

CARD

13

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 107 108

Comments to this Manuals

No comments