Heathkit EUW 24 VTVM Schematic

Page 1

Page 2

HEATH

SPECIFICATIONS

ELECTRONIC DC VOLTMETER

Input Resistance. .............. . .....
Circuit ............................
Accuracy ..........................
ELECTRONIC AC VOLTMETER

7 rms Ranges ......................

7 Peak-to- Peak Ranges .................
Frequency Response (5 V Range) ..........
Accuracy .........................

Input Resistance And Capacitance .........

ELECTRONIC OHMMETER

7 Ranges .........................

GENERAL
Meter ............................

Probes ...........................

Front Panel Controls ..................

Controls Accessible Through Front Panel. . . . .

MUltiPliers. . . . .....................

CircuitBoard..... .............

0-1.5, 5, 15, 50, 150, 500, 1500 volts full scale.
11 megohms (1 megohm in probe) on all ranges,
Balanced bridge (push-pull) using twin triode,

*3% full scale.

0-1.5, 5, 15, 50, 150, 500, 1500 rms scales
(.353 of peak-to-peak).

0-4, 14, 40, 140, 400, 1400, 4000volts full scale.
11 db 25 cps to 1 mc (600 a source).
125% full scale.

1 megohm shunted by 45 [.HLf (measured at
input terminals).

Scale with 10 a center X1, X10, X100. X1000,
XIOK, XIOOK, X1MEG. Measures ,1 8'2 to 1000
megohms with internal battery.

4-1/2", 200 #21 movement, polystyrene case,
Meter terminals brought out to front panel to
facilitate external connections.

Combined AC-OHMS-DC switchingprobe, single
jack input for probe and ground connections.

Function Switch (OFF, AC, DC-, DC+, OHMS).
Range Switch (AC and DC volts, and ohms).
Zero Adjust,
Ohms Adjust,

AC Balance.

DC Calibrate,

AC Calibrate,

1% precision type.

Printed circuit; etched metal process.

Page 2

Page 3

HEATH
Tubes.................... ........
Power Indicator. . .......... .. ..
Battery............... .......
Power Requirements. .. .......

Cabinet Size............. ...........
Net Weight. . . .

ShippingWeight,.,,,,,,,,,, .....

1 - 12AU7, twin triode meter bridge.
1 - 6AL5, twin diode half-wave voltage doubler,

Neon lamp.

1.5 volt, size C flashlight cell.
105-125 volts, 50/60 cps AC, 10 watts,
6-1/2" high x 11-1/2" wide x 5" deep.
4-1/4 lbs.

6 lbs.

All prices are subject to change without notice.
The Heath Company reserves the right to discon-
tinue instruments and to change specifications at

any time without incurring any obligation to
incorporate new features in instruments pre-
viously sold.

INTRODUCTION

The Heath Model EUW-24 Vacuum Tube Volt-
meter has been designed to provide dependable
measurement of AC and DC voltages, and
ohms. The use of 1% multiplier resistors
and a printed circuit board for the tube stages
insure accurate stable circuit operation. Voltage
for resistance measurements is obtainedfroma
size C flashlight cell. A11 operating controls are
located on the front panel; the internal controls
can be adjusted with a screwdriver through small
access holes in the front panel,

A single test probe is used for all measurements.
The handy thumb switch in the probe uses one
position for DC voltage measurements, and
the other position for AC voltage and re-
sistance measurements . In the DC position of this
switch, the 1 megohm isolating resistor in the
probe is switched into the circuit. The test probe
and ground lead are connected to the front panel
of the VTVM through a single plug-jack connec-
tion.

The terminals of the meter in the VTVM are
brought out to jacks on the front panel. These
jacks are intended for use with an external
read-out device, such as the Heath EUW-ZOA
Pen Recorder or the large-scale Classroom
Servo-Meter.

This highly versatile instrument will find many
uses in all phases of electronics. Its accuracy,
high input impedance, damage-proof meter cir-
cuit, and many measurement functions make it
ideal for research, design, repair, and class-
room demonstration applications.

This instrument is one of the units included in
the Malmstadt-Enke EU-100A Instrumentation
Laboratory. It is available as an individual unit,
or it can be purchased at a special group price
when included with the total EU-lOOA system,
The units of the complete EU-lOOA Laboratory
Station are useful not only inlearning electronic
concepts, but also in research and development,
and control instrumentation,