Resistor ladder

The R2R network is a digital value into an analog voltage ( digital-to- analog conversion ).

Usually cheaper and easier than an integrated circuit is a R/2R-Widerstandsnetzwerk, possibly followed by an operational amplifier.

Construction

A R/2R network is made up of resistors with the values ​​R and 2R. The individual input bits are either on ground or on the reference voltage and feed about twice as large resistors ( 2R) as a horizontal part ( R) of the network. Each bit thus contributes its specific part to the resulting output voltage.

Commercial Digital - to-analog converters have such R/2R-Netzwerke integrated into their IC.

Properties

Benefits

  • Very high speed
  • Easy to understand
  • Consists of similar components
  • (theoretically) be expanded without loss of speed to arbitrary precision

Disadvantages

  • Resistors must be as precise same, especially for the high-order bits
  • Many components required ( therefore R2R networks sometimes referred to as " resistance grave ") is
  • The highest bit must (if = 1) a high proportion of the output load drive; Therefore, an operational amplifier will often between each input bit, and the associated resistors connected
Voltage divider
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