Realization Type: Analogical
All systems with realization type: analogical
Systems (19)
Antikythera mechanism
f(x) = astronomical positions, eclipse prediction, Metonic calendar (multi-cycle gear ratios)
A hand-cranked bronze gearwork device built around 150–100 BC — the oldest known analog computer. Turning a single input crank advances 37 meshing gears whose tooth-count ratios encode the periods of ...
Differential analyzer
f(x) = solutions to systems of ODEs (via chained mechanical integration)
Built by Vannevar Bush and Harold Hazen at MIT in 1928–1931, the differential analyzer is a general-purpose analog ODE solver. The core component is a wheel-and-disk integrator: a disk rotates at rate...
Diffractive deep neural network (D²NN)
f(x) = neural network inference / image classification (at the speed of light)
A stack of passive, 3D-printed diffraction layers implements a trained neural network entirely in the optical domain. Each layer is a mask with pixel-wise phase or amplitude modulation, trained offlin...
Kelvin tide-predicting machine
f(x) = sum of sinusoids / tidal height (Fourier synthesis)
Designed by Lord Kelvin (William Thomson) in 1872–73, this special-purpose mechanical analog computer performs real-time Fourier synthesis. Each tidal harmonic constituent (M2, S2, N2 …) is represente...
MEMS accelerometer
f(x) = Newton's second law (a = F/m) — continuous analog acceleration measurement
A microfabricated proof mass (typically silicon, ~1 μg) suspended by folded-beam springs. Under acceleration, the mass displaces by x = ma/k (Hooke's law + Newton's second law in equilibrium). Displac...
MONIAC (Phillips hydraulic computer)
f(x) = Keynesian macroeconomic equilibrium (ODE system)
Built by Bill Phillips (1949). Water flows through tanks and pipes representing economic sectors — income, consumption, taxation, investment. Flow rates encode economic quantities. The system settles ...
Mechanical fire-control computer
f(x) = ballistic trajectory / gun bearing and elevation (multivariate real-time ODE)
Electromechanical analog computers installed on WWII-era warships (e.g. the US Navy Mark 1) continuously computed the correct bearing and elevation for naval guns from up to 25 live inputs: target ran...
Mechanical gyroscope
f(x) = time-integral of angular velocity (orientation tracking)
A spinning rotor mounted in gimbals conserves angular momentum. Any external torque causes precession perpendicular to both the spin axis and the applied torque — rather than tilting directly. By read...
Memristive Hopfield network optimizer
f(x) = optimization via chaotic annealing / transient dynamics
Memristive circuits implementing Hopfield network topology where the intrinsic nonlinearity of memristors creates transient chaotic annealing processes. The chaotic dynamics enable escape from local m...
Memristor crossbar
f(x) = analog matrix-vector multiplication
Crossbar arrays of memristors (memory resistors) perform matrix-vector operations in analog. Voltages applied to rows, currents collected from columns. Resistance values encode matrix elements. Enable...
Op-amp analog computer
f(x) = ODE integration via Kirchhoff's laws
Operational amplifiers configured as integrators, adders, and multipliers solve differential equations in real-time. Voltages represent variables, circuit topology encodes the equation structure. Clas...
Optical correlator (4f / VanderLugt filter)
f(x) = cross-correlation / matched filtering (pattern detection in O(1) optical time)
A 4f lens system consists of two lenses separated by twice their focal length with a holographic or spatial-light-modulator (SLM) filter at the shared Fourier plane. The first lens computes the Fourie...
Photonic integrated circuit (silicon photonics)
f(x) = matrix-vector multiplication / unitary linear transforms (for neural network inference)
Arrays of Mach-Zehnder interferometers (MZIs) and microring resonators on a silicon chip implement programmable unitary matrices in the optical domain. Light encodes values as amplitude or phase; pass...
Planimeter
f(x) = area enclosed by an arbitrary plane curve (∮ via Green's theorem)
A two-bar linkage with a tracing point at one end and a measuring wheel mounted on the tracer arm. When the operator traces the boundary of an arbitrary shape, the wheel rolls only in the direction pe...
Repressilator (synthetic gene oscillator)
f(x) = limit-cycle oscillation / biological clock (via negative-feedback transcription loop)
Elowitz & Leibler (2000, Nature) constructed a synthetic oscillator in E. coli from three mutual repressor genes wired in a ring: LacI represses tetR; TetR represses cI; CI represses lacI. No gene pro...
Resistive sheet (Teledeltos) Laplace solver
f(x) = solutions to Laplace's equation ∇²φ = 0 (electrostatics, heat, groundwater flow)
A sheet of Teledeltos — carbon-coated resistive paper with ~6 kΩ/square resistivity — conducts current that obeys the same Laplace equation as electrostatic potential, steady-state heat conduction, in...
Slide rule
f(x) = logarithm, multiplication, division, roots
Logarithmic scales engraved on sliding rules allow multiplication by physical addition of lengths (log a + log b = log ab). Precision is bounded by engraving quality and human reading resolution — typ...
Thermodynamic computer (Normal Computing SPU)
f(x) = probabilistic sampling / linear algebra via thermal equilibration
Analog physics-based computers using thermodynamic principles for computation. Normal Computing's Stochastic Processing Unit (SPU) uses RLC circuits as unit cells with all-to-all coupling via switched...
Watt centrifugal governor
f(x) = proportional speed regulation (continuous set-point tracking via negative feedback)
Two steel balls are mounted on hinged arms linked to a rotating vertical shaft driven by the engine. As engine speed increases, centrifugal force swings the balls outward and upward; through a collar ...