The operation of both main outputs is identical; the following description applies to both.
Setting Up the Output
With the POWER switch on (l) and the output OFF the output voltage and current limit can
be accurately preset using the VOLTAGE and CURRENT controls; the left-hand meter shows the
set voltage and the right-hand meter shows the set maximum current.
When the output switch is switched ON, the lamp lights; the left-hand meter now shows the
actual voltage and the right-hand meter the actual load current.
Constant Voltage
The output voltage is adjusted using the coarse and fine VOLTAGE controls; the CURRENT
control sets the maximum current that can be supplied.
Constant Current
If the load resistance is low enough such that, at the output voltage set, a current greater than the
current limit setting would flow, the power supply will automatically move into constant current
operation. The current output is adjusted by the CURRENT control and the VOLTAGE controls
set the maximum voltage that can be generated.
The CC lamp lights to show constant current mode.
Instantaneous Current Output
The current limit control can be set to limit the continuous output current to levels down to 10mA.
However, in common with all precision bench power supplies, a capacitor is connected across the
output to maintain stability and good transient response. This capacitor charges to the output
voltage and short-circuiting of the output will produce a current pulse as the capacitor discharges
which is independent of the current limit setting.
Protection
The output has intrinsic short-circuit protection and is protected from reverse voltages by a diode;
the continuous reverse current must not exceed 3 Amps, although transients can be much higher.
The output is protected against externally applied forward voltages of up to 40V.
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