A Key Component: The Operational Amplifier

EAI TR-20 dual integrator network module

Transistorized analog computers often used discrete op-amps in pluggable modules. Their function depended on what they were wired to.

A Key Component: The Operational Amplifier

In electronic analog computers, electrical currents represent numerical values: higher or lower voltage signifies greater or lesser values. Key to this process is the operational amplifier (op-amp), a voltage amplifying circuit.

Combined with other components, op-amps use voltage to add, subtract or multiply by a constant and integrate over time. Op-amps also have diverse uses aside from computers.

A Palimpsest on the Electronic Analog Art

This collection of notes and articles about analog computing was an essential reference for analog computer engineers in the 1950s.

View Artifact Detail
Reacting in Real Time

When bullets and missiles fly, you need to respond swiftly. During World War II, both sides looked to op-amp technology for solutions.

In America, Bell Labs engineer David Parkinson dreamt one night in 1940 of an anti-aircraft gun using the amplifiers he’d developed for telephone circuits. By 1944, the resulting M9 gun director helped destroy 76% of German V-1 buzz bombs.

In wartime Germany, engineer Helmut Hoelzer used op-amps to guide the V-2 rocket. After the war, Hoelzer’s groundbreaking work provided a foundation for America’s Hermes rocket.

M10 Gun Director

The M9 Gun Director and its bigger brother, the M10, was only one part of an anti-aircraft “battery”. Visual or radar tracking provided target information. Up to four 90mm or 120mm artillery guns took data from the director to aim.

View Artifact Detail
V-2 rocket launch

After World War II, captured V-2 rockets—and captured rocket engineers—helped jump-start the U.S. missile program. Helmut Hoelzer brought not only rocket expertise, but also an early analog computer he used in Germany during the War to simulate them.

View Artifact Detail