7412532921

Dynamie Transistor Checker

New Seco Model 100 is a self-contained, self-powered unit which tests a wide rangę of transistor types.

BC-603 FM BECEIYER

20 TO 27.9 MC. %mmQK.

GOVT. RECOMD. ..W*⁹

BC-ISS— FM RECEIYER—27 to

39 I MC .............Ui«d : $24.95

BC-8B4—TRANSMITTER — 27 to

39.1 MC ..............Us«4: $7.93

BC-604 TRANSMITTER—20 to 27.9 MC: Usad: $4.93—N«-N«w: $7.93 FT-237 M*uRtlR« tor Trans. A R*.

c#lvtr—R»-N*w..............$4.95

FT-344— M*u«tlR§ F/Rm«Iv«t Only.....Ra-new: 4.95

OM.34 12 V Dyn F/MC-183-SOS.U : $2.93— R-N: 4.95 OM-35 Dyn. F/BC-SS4-604......U: $7.95— R.N: 9 95

AC POWER SUPPLY PS-403

Output: 220 VDC 80 MA 4 24 AC 2 Ann. Tuba RactiRci. tloR: maunto en raar Plua af BC.S03.SS3 Caa ba adapted ta atbar Racatoars—

KIT: $10.00— Włrad: $14.95

RECEIVERS:

BC-733 Latali lar Rat.—IOS.S to 110.3 MC.Uied:$ 7.95

ARB*Ratai«ar—190 to 9050 KC...........Uird: 18.95

R-23/8C-453 Rat—190 ta 350 KC........Uatd: 14.95

R.27/BC.455 Rtt.—O to 9 MC...........U»ed:    8.95

R.4/ARR.2 Rat.—540-830 KC: 230 258 MC.R-N:    8.95

BC-I20S Baataa Rttatoer—200 to 400 KC.Re-N:    9.93

BC-652 Rataiaar—2 ta 6 MC— Lata 07n ..Utad: 19.05 BC-342 Rataiatr—1.5 to 18 MC Far AC ap. Uitd: 69.50 BC-312 Ratałaer—1.5 ta 18 MC Leas OTn Usad: 59.50 BC-544 Rat.—ISO ta 1500 KC— Far AC ap. Uitd: 49.50

ALL BAND RECEIVER

NAVY AHB/CRV 48151—190 ta 9050 KC—Faur Band. 6 Tuba Suparbat—Latał 4 ramola tuninf and band thanfa: llluminattd dial. Sharp 4 broad tunlng; AVC. CW. praaltlana tor aperatian af DU-I Laap. Camplata with Tuba*: I/I2SA7. I/I2ATS. 4/I2SF7. 4 24 Valt Dynamatar. Slia: P|4 QC 8 a 7 a |S“.... Usad:O • ‘♦•30 A BO V C—Canytrtad ta 12 Valt. witb Dynamatar (Na elettrit

band tbanpa) ...........$21.95

Cenyenian far 115 V 60 tytle witb SPin Dial. Pbana Jatk. CW. Valuma Central. On 4 O Ił Swittb (Ali an frant pana!)

— KIT of Parli witb Imtruttieni............$10.00

Canyartłen—as Abave—far 12 Valt DC—KIT af

Parts, with Dynamatar ..................... IP.no

Remata Central Baa: $2.nO— Remete Central Shaft:    1.50

Rtmete Central Haad ......................... 2.0u

Tuninf Knab far larfe spllned ahaft............ I.uo

T-Sbaft Adapter (ar remata and latał tuninf.....    1.50

PLUCS anly— far Rtteiyer ar Central Baa .Eatb: l.au

KEYERS, TELEPHONES, HEADSETS, MICS.

TS-9 Handset...............Uitd: $2.95—Naw: $ 3.95

TS-13 Handset. w/PL-55 4 PL-68.U: $2.95— N:    3.95

T-17 MitrePhene ...........Used: $3 95—New:    0.95

CM -1 -SC Hand Carben Mit.—Mobile type.New:    fl.il 5

EF.-8 Field Teltpbnnas.. Used: $12.95— Retand.: 10.93

BO-71 Switthbaard—6 Linę.....U : $14.95— New: 24.95

BD-72 Swittbbaard—12 Lina.. .U: $24.95—New: 3195

RM- 29 Central Unit____New: $05— W/Handtet 8.95

RM-52 Cantrol Unit (Pattb Faund.) U:$1.95—N.:    2.95

H-I6/U Headset—8000 ahm.....U : $1.95— New: 2.95

HS-33 Headset—300 ahm.......U: $4.95— New:    7.95

TC-34 Keyer F/Cede Praetite.........Ra-New: 22.95

Cadt Prattite Tapet, inked Paper—15 ta Set.N.: 10.93 J• 45 Tel. Key witb tard and Pluf..........New:    1.50

COLLINS ART-13 TRANS.—$49.50

THE Seco Model 100 Transistor Checker is a low-cost dynamie checker for transistors. The unit is a complctely self-contained, self-powered tester which checks a wide rangę of transistor types either in or out of the Circuit. Transistors under test may sim-ply be plugged into the unit or may be easily clipped into the Circuit with alligator elips aflixed to the external leads.

The unit is designed with a new but proven concept of dynamie checking under currcnt-amplifier conditions. Fast and easy to operate, the checker provides a visual means of observing signal output by means of the glow in a neon lamp. The indicator lamp simultancously checks for (1) opens, (2) shorts, and (3) gain. The unit permits matching of similar type transistors in an actual operating oscilla-tor Circuit. It also providcs for a rapid “go-no-go” test at practical collector currcnts.

The over-all dimensions of the Model 100 are 2^,4x3‘4x6^,/i inches. Ship-ping weight is only 1 pounds. Pricc of the unit is $19.95.

Principle of Operafion

The tester incorporates a specially designed pulse signal generator. The a.c. signal developed in the primary winding of the transformer (see diagram below), when an operating transistor is connectcd to the checker, is stepped up to a voltagc suflicient to fire a neon glow lamp (NE-51). An oscilloscope or a.c. v.t.v.m. may also bc used to check the output of the transistor in the Circuit of the tester.

When using the lamp as an indicator, the brightness is in direct proportion to the signal output. When using an a.c. v.t.v.m. or the oscilloscope to notę output, the lamp switch is opened to pre-vent any clipping that would be caused by the neon lamp itself.

The design of the transformer and the selection of RC components is such that a large rangę of transistors can be accommodated, from small-signal types to power types. The switch on the control knob which allows the user to select the "Power Types" position changes the amount of feedback by un-shorting the 680-ohm resistor. Power transistors are checked at 50 ma. or morę, depending on the transistor type. For "quick-check" operation, the base current control knob is set fully to the left at "0". Then the control knob is advanced to reducc the base current and to establish lower collector current. The higher the dial reading at which a given transistor cuts out of operation. the higher the gain. For "in-circuit” testing, the impedance of the Circuit is such that signal genera-

2 TO 18.1 MC—100 WATT—PHONE, CW. MCW

Tbe mest dcsired Set an tbe surplus market—Easily conytrted ta 10 Matars (Sea Surplus Ceneertien Manuał Na. 2—$2.50). Aulamatit Tuninf far sclettian af II Cbanncls in tbe Freą. Ranfe. Tubę Line-Up: 1/837. 1/813.    2/1625. I/I2SJ7. 2/«V6. 2/811.    2/I2SL7.

I/I2SA7. AC Pawer Suoply refuirements: 28 VOC/lO A. 400 VDC/225 MA 4 1250 VDC/250 MA. SUa: 23* a 16 a II*. wt.: 70 Ibs. Prite. USED: $49.50

Prite—Sama at aboyr—eatept. Lass Tubes...... 30.00

DY.I2/ART.I3 24 V. Oyn. w/Fllter4 Relays—U: 12.95

Complete schematic diagram of transistor checker. The transformer used is a spe-cial unit with a 16 to 1 step-up ratio.

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Front panel view of the transistor tester.

PULSE ANALYZER And OSCILLOSCOPE

IP-I48/APA.IIA RADAR PULSE ANALYZER witb rapatitian Fraa. af 200 ta 6000 CPS witb aithar a naft-tlve ar Pasitiya pulsed sifnal. Has ealibrated dials far pulse widtb 4 rata. Used witb APR-I. APR-4. and atber reteivert. Alsa tan be used at an ottilleseapa. Cemplatt witb I /3 J P2 Cathede Ray Tuba. 6/I2AT7.

2/6AG7. 2/6AC5. 2/2X2. 4 I/SR4 Tubes. Yaltafa rtfuirad: 115 V 400 tytle 4 24 Valts.. USED : S I Q.QR

LAROEST VARIETY of SURPLUS EYER OFFERED! See CATALOO F-591

Moartsi uapl. RN • Ali Prleas F.O.B., Lima. Dbla Minimum Order $5.00. 4 25% Oepesit an all C.D.O.’:

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tion is possiblc with the 1.5-volt bat-tery in the checker.

In using the tester to match transistors, a comparison is madę of the dial reading at which oscillation "drop-out” occurs. Two perfectly matchcd units will stop oscillating at exactly the same position of the control.

To inerease the usefulness of the tester, extra batteries may be attached in series with the collector leads. For morę current loading on power transistors, a 500-ohm pot may be con-nected across the output jacks.

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