Current Sensing

• The current transformer uses a single 12V NPN transistor pickup amplifier
• The signal is coupled to mid-5V to a 4016 analog switch
• Many 4016 outputs can be tied in parallel, where only one is enabled at any moment to drive the PIC A/D input
• The current transformer module is the single transistor with open-collector output, such that only 2 wires are needed to connect to the output pull-up resistor on the interface module

• 12V

• 4.7f

• 2.2k

• 2.2

• 150k

• 20k

• 39

• 2N3904

• 4.7f

• 10k

• 10k

• 5V

• 4016

• enable

• PIC A/D input

• 100-700h

• 2 wire interface

• Current Transformer Module

• Interface Module