B&K 0-30V User Manual

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

17 

 

The working characteristic of this power supply is called a constant 

voltage/constant current automatic crossover type. This permits 
continuous transition from constant current to constant voltage modes in 
response to the load change. The intersection of constant voltage and 
constant current modes is called the crossover point. Fig. 7 shows the 
relationship between this crossover point and the load. 

For example, if the load is such that the power supply is operating in 

the constant voltage mode, a regulated output voltage is provided. The 
output voltage remains constant as the load increases, up until the point 
where the preset current limit is reached. At that point, the output current 
becomes constant and the output voltage drops in proportion to furt her 
increases in load. The crossover point is indicated by the front panel LED 
indicators. The crossover point is reached when the CV indicator goes off 
and the CC indicator comes on. 

Similarly, crossover from the constant current to the constant voltage 

mode automatically occurs from a decrease in load. A good example of 
this would be seen when charging a 12-volt battery. Initially, the open 
circuit voltage of the power supply may be preset for 13.8 volts. A low 
battery will place a heavy load on the supply and it will operate in the 
constant current mode, which may be adjusted for a 1 amp charging rate. 
As the battery becomes charged, and its voltage approaches 13.8 volts, its 
load decreases to the point where it no longer demands the full 1 amp 
charging rate. This is the crossover point where the power supply goes 
into the constant voltage mode. 
CONNECTING TWO POWER SUPPLIES IN SERIES 

Two Model  1735A power supplies may be connected in series to 

provide a variable 0-60 volt output. In this configuration the  power 
supply can supply up to 3 amps. See Fig. 8 for the connection scheme. 

 

When connected in series, the VOLTAGE controls of 

each power supply exercise control over a 0-30 volt range. 
Add the LED display readings together or connect 
external voltmeter across the load to determine the total 
output voltage. 

Load current may be monitored from either supply; the 

readings will be identical since they are connected in 
series. Also, since the supplies are connected in series, it is 
only necessary to set the current limit on one of the 
supplies; the other may be set for maximum.