HP 456A Operating And Servicing Manual
HP 456A Operating And Servicing Manual

HP 456A Operating And Servicing Manual

Ac current probe

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Summary of Contents for HP 456A

  • Page 2 OPERATING SERVICING MANUAL MODEL 456A SER IALS PREFIXED: 103 - AC CURRENT PROBE Copy".ht 1961 HEWLETf-'ACK,UD COM'ANY ISOI 'AGE Mill U.S.A ROAD, 'AlO AlIO, CALIFORNIA. Printed: MAR 1961 00395·1...
  • Page 3: Table Of Contents

    L-l. Bucking Out C a pac itive Component General A rrangement of Model 456A 2-6. of Plate Current Model 456A AC Current Probe ..1 -2. Typical Change in F requency Response 1-3. 3-1 . with Load Capacitanc e . . .
  • Page 4 Section 1 Model 456A Table 1-1 Table 1 -l. Specifications SENSITIVITY: 1 rna/rna ± 1% at 1 kc ± 2%. 1 00 cps to 3 me; ±5%. 60 cps to 4 mc; FREQ UENCY RESPONSE: -3 db at 25 cps and greater tha n 20 mc .
  • Page 5: General Information

    Section Model 456A Paragraph 1-1 SECTION I G ENER AL INF OR MATION The probe ope rates w ith an ac companying small ampli­ 1 -1. GE N ERAL DES CRIP TIO N. fier to convert th e ac c urrent being measured to a pro­...
  • Page 6: Power Requirements

    IOMC 30Me Wh en the 456A is u s e d with th e ac power supply the fREQUENCY chassis is automatically grounded th rough the third prong in the power plug. The three conduc tor �ower c able s u pplied with the i nstru ment is terminated in F igure 1-3.
  • Page 7: Operating Instructions

    This action is a limi­ 1-2 for a list o f Hewlett-Packard instruments s uitable tation of the m eter and not a fault of the Mcxlel 456A. for use with the Model 456A.
  • Page 8: O P Eration

    EOUIPMENT UNDER TEST INSULATED CONDUCTOR BEING MEASURED 1. Connect output of 456A ro a voltmeter or oscil­ 4. Re d c u rrent being m ea s ured on m eter or oscil­ loscope. loscope ( read livol milliampe res).
  • Page 9: Cleaning Probe Jaws

    A n easy method of test­ ing for ground loops is to clip the probe over the 456A The probe jaws should mate perfectly with no air gap output ca ble .
  • Page 10: Lllustrating Directional Effect Of Curren T Mea S U Remen T

    ..---- -- <:... ured w ire to the grounded s h ield inside the 456A probe ..when the probe is clamped around the wire. This capac itance typically has a value anywhere from 1 pf pf, depending upon wire size, insula tion and location w ith in the probe aperture .
  • Page 11 -hp- 456A PROBE HEAD" Figu re 2-6. Bucking OUt Capacitive...
  • Page 12: Equivalent Circuit

    Model 456A Section 1l I Pa ragraphs 3- 1 to 3-3 SECTI ON I I I THEOR Y OF OPER ATION 3 -1 . INTRODU C TIO N . The equivalen t circuit can be thought of as shown in figure 3- 1, where is the current ga in of the tran ­...
  • Page 13: S Ervicing Etched Circui T Boards

    Model 456A Section Figure 4-1 SERVICI N G ET CHED CIRCUIT BOARD S Exc es s iv e heat or pressure can lift th e copper s trip from the boa rd . Av oid da mage by us ing a low power soldering iron (5 0 watts ma ximum) and following these instruc tions.
  • Page 14 Turn (he ins trument OFF. Remove the cabinet as instructed in paragraph The Model 456A is normally wired for 1 15 volt oper­ Remove and disca rd all ba tteries. Replac e the 4-2. a tion unless otherwise specified.
  • Page 15 Since the calibration and frequency response of to the the Mo d e is usua ll y much b e 400D/H/L 470C. l 456A ter than the input of th e in place of the Leave the wires still connected to the 470C.
  • Page 16 WITH THE SAME P OLA RITIES AS MARKED ON 2) Turn on the 456A with no input to the probe. The THE BATTERY HOLDER. Note that the s mall termi­ nal on the battery is negative not positive a s with noise as read on the meter or oscilloscope should be dry c ells .
  • Page 17 WHEN TROU B LESHOOTING. EVEN A MO­ � s tock # 456A - 2 1 A - 8, a new probe cable as sembly, MENT A RY S HORT MAY BURN OUT A TRAN­ be installed instead becaus e of difficulties encountered OR mODE.
  • Page 18 Model Section IV 4!'i fIA F igure 4 - 3 P R O B E CABLE A S S E M B LY ( C OM P LE TELY ASSE MBLED) 4 5 6A - 2 IA- B CROD OT CO N N E CTO R ( S E E TEXT ) 2 1 9 0 - 0 0 1 2...
  • Page 19 Section IV Model 456A Figure 4-4 BATTEAY �.� 2���f -611 PROBE '-R'-A2 -, . _ __ _ _ _ 2N1516 Output 3300 Amplifier 2400 O.OI�f j '\ WIRE CARIIYING CU/III I E NT TO 11£ M£ASIJII£O CLIP LeAD GROUND O.OI�F...
  • Page 21 Thi s s ection contains i n fo rmation for orde ring re­ To order a replac ement pa rt, a ddres s order or in­ ® 456A quiry placeme n t pa rts for the AC Cur rent P robe .
  • Page 22 S e c ti on V Model 4 5 6A R epla c e abl e Table 5 - 1 . Parts Sheet 2 of 4 ) Ckt R ef. D e s c r iption 9 609 5 0 1 50-0008 Capacito r : f ixed, c e ramiC , ±...
  • Page 23 Se c tion Mode l 4 56A Ta ble 5 - 1 . Repla ceable Parts (Sh e et 3 of 4 ) Ref. Descr iotion Stock No. ' Q � RS· R e s i sto r : fixed, composition, 0 1 1 2 1 0 69 9 - 0 00 1 2 .
  • Page 24 Section V Model 4 5 6A P a r t s R epla c e a ble S h e et 4 o f 4) Table 5 - 1 . 'F£; �kt Ref. R S " D e s c r iption r Q ' Stock No .

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