The difference between this block and the previous one is that the load is triggered when the resistance of the sensor rises above a point, which is set by adjusting the potentiometer. Using an LDR, the circuit acts as a dark-activated switch. In Figure 1, we show the block with a simple circuit driving a relay and an indication of the blocks that can be driven by this circuit. The potentiometer must offer values between 2 and 5 times the resistance of the sensor under normal operating conditions.

 

Figure 1    Basic resistive sensor II.
Figure 1 Basic resistive sensor II.

 

 

Datasheets


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