# Resistor network in half bridge rectifier

I have come across the following half bridge rectifier circuit connected across phase R and T. I'm wondering about the large resistor network in parallel with the source. What is the point of this and is there any benefits to it?

Thanks.

• My first response was to recognize that the circuit uses pairs of everything. Sometimes that makes sense (single point failure?) But 20 resistors like that? I can only imagine that there is a high voltage present at the input and the resistors aren't rated high enough unless they are chained up like that. Be interesting to hear a better analysis.
– jonk
Apr 17, 2018 at 8:38
• @jonk even with the equivalent rated single resistor I fail to see what effect it will have on the circuit. The voltage will be the same across it. Apr 17, 2018 at 13:05

The resistors are there to cut the inductive spikes when D022 and D023 are reverse biased. The parallel-serial is to minimize the effect of a failing resistor and also to split the voltage across resistors with lower voltage rating.

The overall resistance is Rt = 680k * 10 / 2 = 3.4M

Voltage per resistor Vr = 0.1 *V

In case of a failing resistor

Rt =680k + 680k * 9 / 2 = 3.7M

Voltage over the remaining resistor

Vr = V * 680 / 3700 = 0.18 * V

• that makes sense Apr 20, 2018 at 7:24