1. Manuals
  2. Brands
  3. Trio Manuals
  4. Measuring Instruments
  5. VT-121
  6. Instruction manual

Trio VT-121 Instruction Manual

Ac voltmeter
Hide thumbs Also See for VT-121:
Table of Contents

Advertisement

Quick Links

Download this manual
T R I O
AC V O L T M E T E R
VT-121
VT-121F
VT-121S
I N S T R U C T I O N M A N U A L

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the VT-121 and is the answer not in the manual?

Questions and answers

Subscribe to Our Youtube Channel

Related Manuals for Trio VT-121

Summary of Contents for Trio VT-121

  • Page 1 T R I O AC V O L T M E T E R VT-121 VT-121F VT-121S I N S T R U C T I O N M A N U A L...

  • Page 2: Table Of Contents

    C O N T E N T S GENERAL FEATURES SPECIFICATIONS CIRCUIT DESCRIPTION FUNCTIONAL CONTROLS OPERATION APPLICATIONS MAINTENANCE • • • • 15 ALIGNMENT CAUTIONS FOR USE PARTS LIST P.C. BOARD (X65-1210-00) SCHEMATIC DIAGRAM...

  • Page 3: General

    The output terminal allows your VT-121 to use as a high-gain, wide-band amplifier. h. The input attenuators are switched by a so-called "logic control circuit" so that a desired range can be selected with use of a remote control device (option).

  • Page 4: Specifications

    3. SPECIFICATIONS Values brackets [ ]are for the F version Operating [Meter Section] temperature: 0 — 50°C. Measurable voltages: 1mV—300V in 12 ranges: 1mV, Relative humidity: 80%. 3mV, 10mV, 30mV, 100mV, [Amplifier Section] 300mV, 1V. 3V, 10V, 30V, Gain: 60 dB ± 1 dB [51 dB ± 1 d B ] . 100V, and 300V full scales.

  • Page 5: Circuit Description

    OdBand - 6 0 dB. In studying the operation of each circuit in your Model 2. Impedance Converter VT-121, please refer to Figure 1, the "Block Diagram", A voltage follower circuit having a FET differantial and the Schematic Diagram on the back cover.
  • Page 6 through-rate, high gain amplifier with a differential input. This has a very good linearity as negative- biased by the voltage detected from the current flowing through the Meter load. In switching, this provides a sufficiently wide frequency band so that phase correction circuit is reset.
  • Page 7 INPUT OUTPUT IMPEDANCE OUTPUT MAIN AMP CONVERTER RELATIVE REF CONTROL RELATIVE RANGE SELECT CONTROL METER ABSOLUTE- MEAN VALUE DET • DC5V POWER A C I 0 0 V / I 2 0 V / 2 2 0 V / 2 4 0 V SUPPLY 50/60 Hz - DC 5 V...
  • Page 8 Figure 3 — Rear Panel View. Figure 2 — Front Panel View.

  • Page 9: Functional Controls

    5. FUNCTIONAL CONTROLS 1) Front Panel (see Figure 2) Power-on indicator 2. POWER: Power ON-OFF switch 3. RANGE: Measurable voltage range selector switch 4. INPUT, 10Mft: Input connector, 10Mft impedance 5. OUTPUT, 600ft : Output connector, 600ft impedance 6. RELATIVE REF: Relative reference control 7.

  • Page 10: Operation

    Otherwise, the DC voltage causes a high surge, which could burn your VT-121 out. 4. Connect the cable to the point to be measure. 5. Turn the RANGE selector 3 until the Meter pointer swings over one third of the full scale.
  • Page 11 A corresponds to 0 dB on the red dB scale, Remote Control, remove the blind plate at the rear of your VT-121. Install and plug the optional con- which is a voltage ratio scale. Since the RANGE nector into the 16-pin connector on the PC board.
  • Page 12 R E M O T E C O N T R O L B O X B O A R D VT-121 C A S I N G Figure 6 - Remote Control (Option) Wiring Diagram. R E M O T E C O N T R O L C O N N E C T O R S...

  • Page 13: Applications

    7. APPLICATIONS The basic use of your VT-121 is to measure sinusoidal wave voltages as an AC voltmeter. In addition, it provides a wide variety of applications as described below. SIGNAL (1)Amplifier Gain Measurement GENERATOR Your VT-121 is capable of measuring an amplifier gain, which is a signal magnification from point A to Figure 7 —...
  • Page 14 (2) Root-Mean-Square and Peak Value Calculations c. For sawtooth waves, their form factor is 2/V3and Your VT-121, an voltmenter of absolute-mean value the crest//J. indication type, reads root-mean-square values of sinusoidal wave inputs. Also, it deflects the pointer in • Absolute mean value = v = 0.9 v.

  • Page 15: Maintenance

    7. Disconnect the voltmeter calibrator and connect a wide-band signal generator to the INPUT connector 4. 8. Set the signal generator frequency to 1 kHz and set the RANGE selector 3 on your VT-121 to the " 1 V " range.
  • Page 16 9. Adjust the signal generator output voltage until the pointer swings to the full scale. 10. Change the signal generator frequency from 1 kHz to 50 kHz. 11. Adjust TC101 until the pointer swings to the full scale. 12. Repeat Steps 2 through 11. C A S I N G M O U N T I N G S C R E W S , 6 P I E C E S...

  • Page 17: Cautions For Use

    5. Be careful of a line noise and similar small noises as your VT-121 is a highly sensitive voltmeter. 6. Do not leave your VT-121 at any of high temperature and humidity places for a long period of time. 7. The VT-121S version, unlike the other two, is equipped with input terminals in place of the con- nector.

  • Page 18: Parts List

    11. PARTS LIST of VT-121 DESCRIPTION REMARKS PARTS NO. CIRCUIT NO. A01-0818-12 Case A10-1417-12 Chassis A20-2715-32 Panel Ornamental panel F version A21-0820-08 A21-0821-08 Ornamental panel S version A21-0819-04 Panel Escutcheon B07-0190-04 B31-0708-05 Meter F version Meter B31-0709-05 B40-0765-14 Name plate...
  • Page 19 DESCRIPTION REMARKS CIRCUIT NO. PARTS NO. Fuse 0.1A F05-1012-05 F11-0914-04 Shield case F15-0703-04 Blind plate F19-0703-04 Patch H01 -2826-04 Packing case H10-2802-02 Packing material, foamed styrene H20-1703-04 Protection cover H 25-0029-04 Polyethylene bag J03-0003-04 Rubber leg J10-0038-03 Bezel J10-0042-03 Bezel assembly F version J10-0043-03 Bezel assembly...
  • Page 20 DESCRIPTION REMARKS CIRCUIT NO. PARTS NO. S01-1505-05 Rotary switch Push switch S40-2506-05 Light-emitting diode X65-1210-00 Main unit F version X65-1210-01 Main unit Input cable CA-41 E30-1824-05 S version X67-1000-00 Input cable CA-36...
  • Page 21 PARTS LIST of X65-1210-00 REMARKS DESCRIPTION CIRCUIT NO. PARTS NO. RESISTOR 1/2W 9.99 M f t ± 0 . 5 % R101 R92-0744-05 Metal film R102 RN14AK2E9531F Metal film 9.5 k f t 1/4W ± 1% R103 RS14AB3A682J Carbon 6.8 k f t ±...
  • Page 22 DESCRIPTION CIRCUIT NO. PARTS NO. REMARKS 6.19 k f t 1/4W RN14BK2E6191F Metal film ± 1% R144 3.74 k f t 1/4W) (R144) (RN14BK2E3741F) (Metal film ± 1% (F version) 680 ft ± 5 % 1/4W RD14BB2E681J Carbon R145 1/4W RN14BK2E3010F Metal film 301 ft...
  • Page 23 CIRCUIT NO. PARTS NO. DESCRIPTION REMARKS VR101 R 12-1002-05 Semi-fixed resistor 1 kSIB VR102 R12-0056-05 100 SIB Semi-fixed resistor CAPACITOR C101 0.047jzF C91-0545-05 Mylar 630WV ±20% C102 CQ93M1H472J Mylar 4700pF 50 WV ± 5% C103 CQ93M1H222M Mylar 0.0022MF ± 2 0 % 50 WV C104 CQ93M1H222J...
  • Page 24 DESCRIPTION PARTS NO. REMARKS CIRCUIT NO. Ceramic 0.1 uF + 8 0 % - 2 0 % 50WV C141 C K 4 5 F 1 H 1 0 4 Z Ceramic 12pF ± 5 % 50 WV C142 CC45SL1H120J Ceramic CC45SL2H020C C143, 144 ±0.25pF...
  • Page 25 DESCRIPTION REMARKS CIRCUIT NO. PARTS NO. MISCELLANEOUS Pin connector CON101. 102 E40-1611-05 F10-1518-04 Shield plate F11-0915-04 Shield case Relay S51-1503-05...

  • Page 27: Schematic Diagram

    13. SCHEMATIC DIAGRAM The circuit elements may be changed without notice owing to a technical innovation.
  • Page 28 p r o d u c t o f T R I O - K E N W O O D C O R P O R A T I O N 17-5, 2-chome, Shibuya, S h i b u \ a - k u , T o k \ o I b u , Japan ©...

This manual is also suitable for:

Vt-121fVt-121s

Table of Contents