1.2mV
2.2mV
4.2mV
1.2mV
2.2mV
4.2mV

Figure 5-2.Constant Voltage Load Regulation

Test Setup

correct polarity.

c. Turn CURRENT controls fully clockwise. d. Turn on supply and adjust VOLTAGE con-

trols until front panel meter indicates exactly maximum rated output voltage.

 

e. Differential voltmeter should indicate the

following:

10 ±0.2Vdc

 

6259B, 6260B

 

6261B

20 ±0.4Vdc

 

6268B, 6269B

40 ±0.8Vdc

5-11

Load Regulation.

EOUT in the

 

Definition: The change

 

static value of dc output voltage re-

 

sulting from a change in load resist-

 

ance from open circuit to a value

 

which yields maximum rated output

 

current (or vice versa).

5-12

To check the constant

voltage load regula-

tion,

proceed as follows:

 

 

‘a. Connect test setup shown in Figure 5-2.

 

b. Turn CURRENT controls fully clockwise.

 

c. Turn on supply and adjust VOLTAGE con-

trols until front panel meter indicates exactly maximum rated output current.

d. Read and record voltage indicated on differential voltmeter.

e. Disconnect load resistor.

f. Reading on differential voltmeter should not vary from reading recorded in Step (d) by more than the following:

6259B, 6260B

6261B

6268B, 6269B

TM 11-6625-2958-14&P

5-13 Line Regulation.

Definition: The change EOUT in the static value of dc output voltage resulting from a change in ac input voltage over the specified range from low line (usually 207 volts) to high line (usually 253 volts), or from high

line to low line.

5-14 To check the line regulation, proceed as follows :

a.Connect test setup shown in Figure 5-2.

b.Connect variable auto transformer between input power source and power supply power input.

c.Adjust variable auto transformer for 207 volts a c input.

d.Turn CURRENT controls fully clockwise.

e.Turn on supply and adjust VOLTAGE con- trols until front panel meter indicates exactly maxi- mum rated output voltage.

f.Read and record voltage indicated on dif- ferential voltmeter.

g.Adjust variable auto transformer for 253V

ac input.

h.Reading on differential voltmeter should not vary from reading recorded in Step (f) by more than the following:

6259B,6260B

6261B

6268B, 6269B

5-15 Ripple and Noise.

Definition: The residual ac voltage superimposed on the dc output of a regulated power supply. Ripple and noise may be specified and measured in terms of its RIMS or (preferably) peak-to-peak value.

Ripple and noise measurement can be made at any input ac line voltage combined with any dc output voltage and load current within the supply's rating.

5-16 The amount of ripple and noise that is present in the power supply output is measured either in terms of the RMS or (preferably) peak-to-peak value. The peak-to-peak measurement is particularly important for applications where noise spikes could be detrimental to a sensitive load, such as logic circuitry. The RMS measurement is not an ideal representation of the noise, since fairly high output noise spikes of short duration can be present in the ripple without appreciably increasing the RMS value,

5-17 Ripple Measurements. Figure 5-3A shows an incorrect method of measuring p-p ripple. Note that a continuous ground loop exists from the third wire of the input power cord of the supply to the third wire of the input power cord of the oscilloscope via the grounded power supply case, the