why a diode bridge 1

[DYV1973]

LS,

In the input circuit of a measuring instrument also a diode bridge is placed (behind an opto-coupler). The input circuit is connected to another instrument with a voltage free contact. It is simply used to measure the frequency of the incoming pulses (between 1 and 10 Hz).

Why is a diode bridge placed in the input circuit? Can it be used to protect against induced currents/voltages, due to capacity in a long cable?

DYV

 

[itsmoked]

A diode bridge converts the input to a single polarity. This often greatly simplifies the system, and hence reduces cost.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

As Keith says, the bridge will correct inverted signals and render AC signals into DC pulses of the proper polarity for the counting circuit.
The the bridge will convert the positive and negative half cycles of AC into all the same polarity, doubling the frequency of the pulse train. The instrument must be designed with this in mind.

Bill
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