Reverse Voltage Loading; Reverse Current Loading - HP 6177B Operating And Service Manual

3-32 REVERSE VOLTAGE LOADING
3-39 Diode CR34 is connected internally across
the supply". Under normal operating conditions,
the diode is reverse biased (anode connected to
negative terminal). If a reverse voltage
is
applied
to the output terminals (positive voltage applied to
negative terminal), the diode will conciuct, shunt-
ing current across
it.
This diode protects the
series transistors and drivers.
3-40 REVERSE CURRENT LOADING
3-41 k-. active load connected to the power supply
3-6
may actually· deliver a reverse current to the power
supply during c portion of its operating cycle. An
external source cannot be allowed to pump current
into the supply without loss of regulation. Diodes
CR35 and CR36, connected in series with the neg-
ative output lead, protect internal components
from damage by blocking these reverse currents.
However, to avoid regulation degradation, it is
necessary to preload the supply with a' dummy load
resistor so that the power supply delivers current
through the entire operating cycle of the load de-
vice.