A voltage ladder is a simple

electronic circuit An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or Conductive trace, traces through which electric current can flow. It is a t ...

consisting of several

resistor A resistor is a passive two-terminal electronic component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active e ...

s connected in

series Series may refer to: People with the name * Caroline Series (born 1951), English mathematician, daughter of George Series * George Series (1920–1995), English physicist Arts, entertainment, and media Music * Series, the ordered sets used i ...

with a

voltage Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a Electrostatics, static electric field, it corresponds to the Work (electrical), ...

placed across the entire resistor network, a generalisation of a two-resistor

voltage divider In electronics, a voltage divider (also known as a potential divider) is a passive linear circuit that produces an output voltage (''V''out) that is a fraction of its input voltage (''V''in). Voltage division is the result of distributing the i ...

. Connections to the nodes provide access to the voltages available. Voltage ladders are useful for providing a set of successive voltage references, for instance for a

flash analog-to-digital converter A flash ADC (also known as a direct-conversion ADC) is a type of analog-to-digital converter that uses a linear voltage ladder with a comparator at each "rung" of the ladder to compare the input voltage to successive reference voltages. Often thes ...

Operation

voltage drop In electronics, voltage drop is the decrease of electric potential along the path of a current flowing in a circuit. Voltage drops in the internal resistance of the source, across conductors, across contacts, and across connectors are unde ...

occurs across each resistor in the network causing each successive "rung" of the ladder (each node of the circuit) to have a higher voltage than the previous one. Since the ladder is a series circuit, the

current Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (hydr ...

is the same throughout, and is given by the total voltage divided by the total series resistance (V/R_eq). The voltage drop across any one resistor is I×R_n, where I is the current calculated above, and R_n is the resistance of the resistor in question. The voltage referenced to

ground Ground may refer to: Geology * Land, the solid terrestrial surface of the Earth * Soil, a mixture of clay, sand and organic matter present on the surface of the Earth Electricity * Ground (electricity), the reference point in an electrical circ ...

at any node is simply the sum of the voltages dropped by each resistor between that node and ground. Alternatively node voltages can be calculated using voltage division: the voltage drop across any resistor is V×R_n/R_eq where V is the total voltage, R_eq is the total (equivalent) resistance, and R_n is the resistance of the resistor in question. The voltage of a node referenced to ground is the sum of the drops across all the resistors, but it's now easier to consider all these resistors as a single equivalent resistance R_T, which is simply the sum of all the resistances between the node and ground, so the node voltage is given by V×R_T/R_eq.

References

{{DEFAULTSORT:Voltage Ladder Analog circuits