Keithley 2750 User Manual page 270

Model 2750 Multimeter/Switch System User's Manual
Figure 9-4
Controlling externally powered relays
33V
Digital Output #1
Flyback Diode
Control
Line
Equivalent Circuit
Flyback Relay
Diode Coil
Model 2750
+5V
4.75kΩ
Pull Up Resistor
+
External Power
(+5V to +33V)
-
Transistor Switch
Limits and Digital I/O
Pin 7 - Diode Clamp
Relay
Coil
Digital Output
Pin 9 - Digital Ground
9-9
+
External Power
(+5V to +33V)
-