Symmetrical T and H Attenuator Nomograph
May 1959 Electronics World

May 1959 Electronics World Table of Contents  Wax nostalgic about and learn from the history of early electronics. See articles from Electronics World, published May 1959 - December 1971. All copyrights hereby acknowledged.

Even after computers became commonplace in cubicles and laboratories, engineers and technicians kept design nomographs around for cobbling together attenuators, filters, voltage dividers, etc. Trade and hobbyist magazines like Electronics World used to print them as full-page features on a regular basis, and I have posted many of them on RF Cafe over the years. This particular "Symmetrical T & H Attenuator Nomograph" appeared in a 1959 issue. Maybe the editor thought that "Symmetrical T, H, O, and Pi Attenuator Nomograph" would be too long of a title and that's why the "O" and "Pi" was omitted even though they are clearly included in the chart. As can be seen by inspection of the circuit constructions, the T and Pi configurations (top row) are "unbalanced" while the H and O configurations (bottom row) are "balanced." A quick WWW search turns up plenty of attenuator design apps that not only solve for the exact theoretical values of resistors but also will select the nearest standard value resistors. Some will even then calculate the resulting attenuation value based on those non-exact resistor values.

Symmetrical T & H (and O and Pi) Attenuator Nomograph

Nomographs / Nomograms Available on RF Cafe:

- Symmetrical Reactance Chart

- Parallel Series Resistance Calculator

- Transformer Turns Ratio Nomogram

- Symmetrical T and H Attenuator Nomograph

- Amplifier Gain Nomograph

- Decibel Nomograph

- Voltage and Power Level Nomograph

- Nomograph Construction

- Nomogram Construction for Charts with Complicating Factors or Constants

- Link Coupling Nomogram

- Multi-Layer Coil Nomograph

- Delay Line Nomogram

- Voltage, Current, Resistance, and Power Nomograph

- Resistor Selection Nomogram

- Resistance and Capacitance Nomograph

- Capacitance Nomograph

- Earth Curvature Nomograph

- Coil Winding Nomogram

- RC Time-Constant Nomogram

- Coil Design Nomograph

- Voltage, Power, and Decibel Nomograph

- Coil Inductance Nomograph

- Antenna Gain Nomograph

- Resistance and Reactance Nomograph

- Frequency / Reactance Nomograph