Procedure to determine the state of N ideal diodes in a multi-diode network The v – i characteristic of an ideal diode is shown in Fig.
1.1,2 When the diode is forward biased it can be replaced by a short circuit and when the diode is reverse biased it can be modeled as an open circuit. To determine the state of N ideal diodes in a network, the following step-by-step procedure, termed the ‘bucking battery method’, can be used: 1 Remove any N–1 diodes.
2 Determine the state of the one remaining diode and replace it by a short if it is on or by an open if it is off. If it is on, monitor id through that diode and if it is off, monitor Vd across that diode.
3 Look into the terminals of N–1 diodes and compute the Thevenin voltage, Eth.
4 Insert in series with each of the N–1 diodes a battery, of potential E > |Eth,max|, bucking it so that all N–1 diodes are reverse biased (off). We then have, in effect, gone from a circuit of N diodes where all diodes are unknown to a new circuit of N diodes where all diode states are known. As the (N–1) bucking batteries (E) are reduced to 0 (simultaneously) we return to the original circuit.