Power supply & demand

Alix Paultre, Editorial Director, PSD



Alix Paultre, Editorial Director, PSD

Supply and demand are old concepts that strongly figure into almost every aspect of our lives, and come to bear especially on our electronics. The focus on which of the two aspects of exchange to focus on at any given moment is often determined by factors having nothing to do with facts, and everything to do with perspective.

As nature is predatory, our focus as animals is often on supply. The supply of resources to one with apparently fixed needs is a constantly pressing concern. As mankind evolved beyond basic animal needs, our ability to address supply issues with farming and better food storage kept our focus on maintaining sufficient supplies to manage apparent demand.

This often leads to the incorrect assumption that managing the supply is the goal to stability and growth. The other side, demand, is often as easy to manage and control. Extending the supply by managing demand is usually done in extreme situations, and is often looked upon as negative. Nobody wants to be rationed in anything they want to have, and any such management is viewed upon as controlling and dictatorial.

Engineering is one of the few areas where resource and demand management can be dealt with in a way transparent to the user. For example, saving weight in the space shuttle by deciding the disposable external didn’t need a paint job saved over 600 pounds. Many engineering decisions aren’t that cut-and-dried, but calculations on structural integrity from spacecraft to bridges factor in as much weight savings as possible with the resulting bridge still able to carry the desired weight and traffic. You don’t see people demanding more steel in their bridges, because they do not perceive the compromises involved.

In electronics, this issue is complicated because the marketing department actively and frequently armchair-quarterback the device designers, and the market itself is full of opinion based on incomplete observation and half-truths. Many people think all issues with portable devices can be eliminated by simply putting in a bigger battery, when reducing the power consumption of the device can accomplish the same or more.

The problem of battery size vs. product energy usage can be addressed with the latest new core technologies and low-power MCUs, sensors, and components, and as they mature and become part of the industry’s palette of solutions, people will eventually stop caring how big the battery is. We will eventually be at a point where most personal consumer devices can run on harvested or low levels of standby power from existing battery tech, and the issue will be moot.

This is where one would say the future is coming, but as in many cases, there are existing examples worth noting. There is already a mainstream personal harvested-energy tech that has been around for ages, called the automatic watch movement. Not only has this tech been perfected in purely mechanical form, one can buy quartz-based electronic watches that use the energy-harvesting movement to charge a capacitor to power the system.

The clock has been an inspiration and reference to technology since its invention, and through time was used to compare and contrast other tech to. We used to say “clockworks” to describe internal gearworks in any device, and still use the term “complicated” to talk about devices with multiple functionalities. I propose we take yet another term from watches to use today, “automatic” for devices that can operate on harvested power indefinitely.