Campbell Scientific CR10X Measurement and Control System - Manual (Page 225)

SECTION 14. INSTALLATION AND MAINTENANCE
14-9
through a relay. Figure 14.10-2 illustrates a
circuit for switching external power to a device
without going through a relay. If the peripheral
to be powered draws in excess of 75 mA at
room temperature (limit of the 2N2907A
medium power transistor), the use of a relay
(Figure 14.10-1) would be required. Other control port activated circuits are possible
for applications with greater current/voltage
demands than shown in Figures 14.10-1 and 2.
For more information contact Campbell
Scientific's Marketing Department.
FIGURE 14.10-1. Relay Driver Circuit with Relay
FIGURE 14.10-2. Power Switching without Relay