Diode Circuit - Siemens SIMATIC S7-200 Getting Started

Appendix A

A.2 Diode Circuit

A.2

When diodes have been used in "old" circuit diagrams converting them into ladder diagram

terms is not an altogether simple matter.

Since diodes represent connection lines in principle but only conduct current in one direction,

a similar solution is adopted here as with the bridge circuit. For ease of comparison with the

circuit diagram, the ladder diagram is arranged vertically again.

Three current paths are possible with this circuit: Over switch d, switch e and switch f.

The current through the diodes can only flow from b to d or from c to e.

The three current paths result in the three framed sub-networks in the ladder diagram

solution. Since switches d, e and f are on the same rail as output G, these three sub-

networks have also been linked to form one network.

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Getting Started - Advanced

Training Documents, 09/2007, A5E01469795B