Monthly Photo Competition #20 – July, 2024 – “Bridges” [Poll added]

This is the monthly thread for July , 2024. The topic this month is “Bridges”, chosen by Spiderman.

The general rules for the competition are here.

One entry per person per month . To make the photos easier to review please only post just once to this thread, with your entry. Your post can include a caption with whatever info you want to give.

Once the submission deadline has passed, I’ll put a voting poll in this thread .

Submission deadline: Friday, July 26, 11:45 pm US EDT

Good luck!

Canal St Railroad Bridge Chicago as seen from a river cruise. Now a landmark it’s a vertical lift bridge in use in the early 1900’s it could rise 111 ft in 45 seconds. Taken with an I phone in my right hand an old style in my left. ‍↔

A bridge rectifier, made from four diodes, in front of an oscilloscope display showing what it does.  An alternating current (AC) signal is being fed into it via the black and white wires, and is displayed on the upper trace of the oscilloscope.  The ticked line on the oscilloscope grid, over the upper trace, indicates the zero-volt point.

The lower trace shows the direct current (DC) signal coming out of the bridge rectifier, via the red and green wires.  The line at the bottom of the waveform shown on that trace, is the zero-volt point.

A diode lets current flow in only one direction.  A bridge rectifier has the four diodes arranged so that whichever side of the AC signal is positive will only flow through the diode that is pointed toward the positive DC output, while whichever side is negative, will only flow through diode pointing toward the negative DC output. As the AC signal switches direction, which diodes it flows through switch accordingly.

Note that the output frequency of the DC signal is twice that of the AC signal, and is at zero at the same time that the AC signal is at zero, and goes positive as the AC signal goes either positive or negative.

If you were going to use this as a power supply, you’d probably want to put a big capacitor on the output of the bridge, to smooth out the ripple, and possibly a voltage regulator after that.

The Golden Gate Bridge on a summer night

Confederation Bridge.

Vermilion, Ohio bridge taken from my seat at a restaurant on the river.

Thomas Creek Bridge, southern Oregon coast.

Who needs a bridge when you can fly?

I have so many bridge pics. But, this one is very recent, so I chose it for the contest:

Double rainbow over the 32nd St. bridge crossing the Animas river in Durango, CO.
Historic Durango & Silverton Narrow Gauge Railroad tracks in the foreground.

The Mighty Mac (Mackinac Bridge) from a different perspective.

Charles Bridge, in Prague

Moon Bridge at the Fort Worth Japanese Gardens

Deception Pass Bridge - Whidbey Island, WA

Brian

I don’t have an entry. I thought you’d all enjoy knowing about photographer David Plowden. I bought his Bridges book when I was studying landscape history in the early 1990s. Then, by chance, my neighbor since nine years ago, a historian/photographer, is an acquaintance of Plowden.

Alerted by Plowden’s photos, I visited the Tunkahannock Viaduct (spelling?) in the 90s. It’s in rural Pennsylvania, about an hour from Scranton. It’s rather like the Pont du Gard (Roman aqueduct) in southern France.

A footbridge across a flowing stream in New Hampshire in early September.
(reduced resolution to fit imgur size limits)

The backyard at my old workplace.

The Two Bridges, Folsom, CA:

One of my favorite places to visit back in the day. The embassy is in Old Town, so I went there on a daily basis when working in Prague.

Kenilworth Aquatic Gardens Washington DC

Plank Bridge Perdido Key Florida. When I was a child the bridge was loose planks on fallen trunks. My family often fished our dinner there. Still planks, it survives, perhaps not for long.