Campbell Scientific CR200/CR200X-series Dataloggers - Manual (Page 63)

Section 5. Measurement and Control Peripherals
In other applications it may be desirable to simply switch power to a device
without going through a relay. FIGURE. Power Switching without Relay (p. 51)
illustrates a circuit for switching external power to a device without using 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
is required.
Figure 34: Relay Driver Circuit with Relay
Figure 35: Power Switching without Relay
5.2 Other Peripherals
5.2.1 TIMs
Terminal Input Modules (TIMs) are devices that provide simple measurement
support circuits in a convenient package. TIMs include voltage dividers for
cutting the output voltage of sensors to voltage levels compatible with the
CR200(X), modules for completion of resistive bridges, and shunt modules for
measurement of analog current sensors.
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