7.' WNTI CA~OpB POLlPY!!!

A vacuum tube c11'Ou1t which 1a oapable ot about

t

150 ma out-put currents and whioh baa a verr low incremental outout-put 1mpedance has been dea1ped tor uae w1th the tour diode bridge gate. This circuit which haa a non-linear plate load reaiatance i8 111ustrated in Fig. 7-6. !be combination ot the aener d10de Dl 1s and resistance RL torm the DOD-linear plate load. the other zener d10de D2 1s

u.ed to couple the plate ot '1 with the grid ot T2. A COMplete plecewiae liB . . r anal,.i. ot th1a 01rcu1t i8 ·lncluded 1n Appendlx II. '1'he lapoJ'taat reaulta oan be e.al1J 8Wl1JU!l1'1aed. The clrcuit 11 capable ot • poaitive output current ot ~ - Ea. The b.egat1ve out Plt eurreftt can be 8a hish a. Be. Both

-

^rp ot r Pth.ee currents ⁸re

JIIlX1mwI currents outputs caloulated w1thout driving an,. grid posi-t1ve. 'l'he incremental output realatlnce .ear the po1nt where 19 • 0

i. given 1n Bq. 7-5. 1n the output :reSi8t.ftCe tor oODlparativelr _11 positive values ot output current. 'fo prevent this breakpoint trom interfering

vith the sJst... atabl11tJ 1t haa been shifted bJ app17ing a current

----

⁰ic + ec

Fig. 7-5 A Real Capacitor

T 5687

+300

-150V

I fa

Ez^=120V

e_z= 350V _ +

l

^R^,

Iel

250K.o.

-300

.'0011-'-f

-Fig. 7-6 White Cathode Follower with Non-Linear Plate Resistance

.rI

- 20-1

--150 -100

~

^> ¹⁰¹

w o

o io (rna)

---I

I

-+---+---·0

---+----+--+-

+---+--+----

---t---50

t

⁵⁰ ¹⁰⁰ ¹⁵⁰

-10

--~---o_

__

^o~20

Fig. 7-7 ^White Cathode Followerrs Output Characteristics

TI-2N498

.lfLf

-25V

4.3K.o. 47K.o.

-50V +25

100.(1

270£1

~

PJlse Width Adjust.

Fig. 7-8 Transistor Blocking Oscillator

CK5755

Tr

^Storage

rapacitor

Plg. 7-9 output Burter

+ 45V

-,--...-... --;11.---0

Trigger Source for 4 Diode' 270.(1 Gate

Note: All Diodes Transitron SG222

104

CK5755 18 espec1ally des1gned to keep gr1d leakage current at about lo"9ampa • 'rh18 our rent 18 less than the ourrent through the gate.

Thi8 tube is used ^8S a cathode follower in the output burter. The cathode reaistor ot the cathode follover must be kept h1gh (about

1 meg) 1n order to take advantage ot the tubes spec1al properties.

Thi8 high resistnace 1n the cathode follover prevents the oircuit from being loaded down. Another cathode follover tollows this first cathode follover in order to IIIke the output ot thi8 stage IIOre

usable. A bias adjustment 18 a180 provided in the circuit.

APPENDIX I

The 88 va ig plot tor the tour ^~iodebridge 81te can be obtain-ed by a graphical procedure G Bqa. '-218 and 3-2lb from which this procedUre i8 de1'1 ved are repeated heN tor convenience.

'.218

'.2lb The stepa belov are tollowed to determine a single point on the

8g va 19 plot.

1) plot t [

~

^] ^va ¹⁹ ^to-ran arb1t-r8l'Y

~

2) plot

t'[~J

^va ¹⁸

3) add 1) aDd 2)

4) plot

B.r - t.,:a

T (include ^he:re tr1ge-r source non 11n-ear1tl •• )

5) l11ael'llectlon ot ') and 4) are pos8ib1e operating points.

6) cOJlpute as b7 subtraoting 1) and 2)

7) plot 8S va ^1s (one polnt, wlth ~ 88 a parameter) 8)

trr

^agaln^to-r^another^iT⁽ⁱ^{e .}^{so back}^to¹⁾

It in followlng th1s pPOoedure

3)

aDd

4)

don't lnt.react, the value vhich vaa arb1tJ'llr111 choan tor

1.r

^can^{na •• r} ^occur. ^While^this

procedure

mar ••••

^rather^t~.coaaum1uI at first B~8nce. 8 good estimate

ot .s

^va ^i£can actual1,. be obta1n~ rather qulckly in practioe. It lT 1_ a cu-rl'8llt source on11 the subtraction ot Bq.

,-21b need b. pertoNed.

®--~ ---0

Fig. Al-l Graphical Construction Used to Find eg ^VS. ig Plot for Four-Diode Bridge

APPENDIX II

The piecewise linear analys1. ~f the Wh1te CathodeFOllower

18 outlined below. It i8 always assumed that the oUl"rent through D2 is 8 small percentage ot the current through Tl • This appl'Ox1-mation allows us to neglect the b1as resistor which goes trom the gr1d ot T2 to the -300 Volt

supply-Equations tor Both tube in 11near range and Dl DOn conducting.

..

s"l l"p - .... eel

..

1b2 rp - 11 .c2

..

ⁱ b1 R + e_b1+ e_{b2 ...} Be

1\ ..

ⁱb1 R + _ez + e_{C2 ...} Be

ib2 + 10 .. 1bl

g1ven B1n, 10 ^find ⁸b2, eb2 , ⁱb2 , 1

b2,

ecl ' ec2

0 rp 0 -1 0 _-~ 0 1bl

0 0 l"p o -1

o

-11 _lb2

~ + Eo ₌ R 0 1 1 0 0 -bl

~ + Ee - e z ^R ⁰ ⁰ ⁰ ⁰ ¹ ~2

E1n + Eo ⁰ ⁰ ⁰ ¹ ¹ ⁰ eel

l

^io ¹ ^-1 ⁰ ⁰ ⁰ ⁰ ·02

L1sted beloy are the total equat10ns tor the White Cathode tolloweria ourrents and voltag ••

FiG- A2-1 ^{The Whi}te Ca.thode Follower

Incremental r p Resistance

77

e o (i=O)/

e -E

"'E, +~

"" In fL

Incremental rp-+-R Resistance

--p:-Incrementol r p Resi stance II'

. _ Eb+ 1+t'ifL _{Ec- ez}

10 - R

. Ez

lo=T

Fig. A2-2 Wnite Cathode Follower's Theoretical Output Characteristics

103

D~l

^-= D1 .. 10 [(1 + JJ.)r_{p ]} + JJ. R_in

+[

¹ ⁺^tJ.

+

",,2 JEb + +

r 1

⁺

2

^tJ. ^{+ ....}

2] EC

⁺

[_""_1'2]

Dib? ^l1li

D~

^..

[-1'

^{P - (1} ⁺^I'^{+ ....}

2)~

^]¹⁰⁺^tJ. E1n + [ J + tJ. + ",2]'\,

+ [1 + 2tJ. + 112

J

^Ee⁺[.'-".f.12

J .z

Debl .. D} .. [rp2 - .... l'p R ] 10 + [-11 rp-IlR-f.12 R ] Ein + [rp

+ '2 .... r p] Eb + [r p + tJ. l' P -.... R ... 2 R ] E c + [-.... 1' P + '-" 2F ] e z

Deb2 ^l1li D4 .. [- l'p2 - l'pR ] 10 + [1l2R + ""l'pJ E1n + [ l'p - Ill' p]

~

+ [rp + .... 2 It JEe + [ JJR + aAr p ] sa

Decl .. D5 .. [rp2 + I'pR J1₀ + [2rp + R + alRJ Bin + [- rp + ",,1' P

J ~

⁺ ^[R⁺ ^tJ. ^R⁺^{r p} ⁺^{Ill' P}

J

^{Ke + [ -} ^Ill'^{P •} ^{tJ.R ..}

J

^e^IS

Dee'2 ^l1li D6 .. [- l'pR - p.rp R ] 10 - tJ.R 11n + [2l'p + tJ.^r_{p ]}

~

+ [21' P + ^J,Ll'P .. t.&R

J

^Ee+ [ - R - tJ.r p - 21' P ] e z When T2 cuts

orr

the follow1ng equations apply' 1b2 ^l1li 0

i ^l1li tJ. Eill+[1+U+J!21Eb+[1+2!+ij2 JEo -["+11:2

l5'i'

^D1 ^J ^{D .} ^D'

.0 -

~R B1.-~

^{, -}

h!+~Vl+ .. ^l

D D D

D1 .. r p + (1

+

tJ.

+ ....

2 ) R

E 1 im1ne, iag Bin

tJ. R 10

·.0 ..

^~⁺⁽¹⁺tJ.) Be - ... s The equation vi th f 2 cut ott 18 then

e o - ^{.. i}o

The equation below app11es only at the point or cutoff.

110

eo • lL~21t ^{Kin -} ~ ^Ii,'" ^[rl2

⁺

~][l

⁺

^If] ^Be

⁺

^a ^[r¥

⁺

Ill ••

or ^~

^D1 ^D

The next break po11'1t Vill OCCUr when Dl beg1ns to con.duct at 10 • E ..

r

e o •

R.. - E

- " ₁+ ~' z

!he •• equationa are lOad until eel soes positive a t .o - ⁰ ¹⁰ ^• ^{Eb - B}z - ^B1n

A break po1nt vill occur tor negat1ve 10 vhen the gr1d of '2 goes pOsit1ve. eel • 0

The results of these calculations are summarized in Fig. A-2.

BIBLIOOltAPBY

1. Rubinott. II., "Aoalogue

va.

^DigItal CODlputer8-A Comperison,"

~1'00U91PR ot

th!

IU. Vol • .la,

,p

l25~-1262, October, 195'.

2. K81U1edl, O. W ...

MNa

^j Apalos-ifS1t,t'1 F1.1&!:t Simulat1011, M.I.1'. SeJ'VOllecbi au ., eourse , .

I.

'l'heais" "swar,., 1959.

-4. R4fhe ^PUlsed Analog DeDlOutretlolt Computer," Flnal DflNaonat:rat1on Report 45-1, DSR p:roJeot 1591, M.I.'1'. Sel"vomecbal11sl'II8 Lab., April, 1959.

5.

ltea:oed1,

o. w.,

Morot'l81. R., and Mo1'8e. H ... An EX~:rl~ts1

Aatl$f-ijS1tal P'1~t §M1ator M.l.T. Servomecfiii smat).,

~.po

-2, d£.

au. §. .

6. van

^{Rena •• ,} ^{A. B ••}^Tbe

ttwh1t."

^CathodeFollower, Bl1gIneerlng

Memo~dua

.0.

2}, DIC Project 6663, M.I.T. ServomechanIsms Lab., Wov., 1950.

8. libera, J. 1. aDd _11, J. L. , "Larg .... Slgn.l Bebevtor ot Junct10n 'l'reutatora

"F.9!!41W

ot the I~ Vol. 42, fJp 1761-1712,

December, 195 •

9. 11011, J. L., "Large-Slsnal 'l'reuslcmt Itesponae of' JUnction Trau1.toN," b:20eedIM! 9( the IRE Vol. 42, :P1' 17~';'1784,

December, 195-. .

10. SUran. J. J., "Tran.1ator Monoatable Mu1tlvibrators for pulse G.eretio •• " Prooeeding of the IRE .. Vol. 46, pp 1260-1271, JuDe, 1958.

11. Eddins, W. 'I... "sallSple aDd Hold Circuit. tt

}.ZS

IR!; NatiOft8,l

C9lV8Dt19P

IIecon'

Vol. 6, Part 5, ^pp21-25.

14. Von H1ppel, A., Editor, D1eleotr1cJJ!ter1als and A:epI1oat1ona, The Technology Preas ot

M.!.T.

^i95~. ¹

16. Hana11toD, D., "'l'Nu1.tor Pulse Geuerstol' For Digital Syatem" ^I IRK Trell.act1ons OD Electronio Computers, Vol. EC-'! ^I pp. 244-249, Sept., 1958.

113

Im Dokument ot at (Seite 108-122)