How to Get Started with LED

Connect a LED with a battery and a resistor. The long leg of an LED is the positive, the anode. You could connect a LED directly to a battery without a resistor, but that probably wouldn’t last very long. The resistor acts as a load and limits the amount of current in the circuit. When just starting out, you don’t need to worry about the technical details, just know that it’s best to add in a resistor when wiring a LED. For my example, I’ve chosen a ~5VDC power source (3x AA batteries, 4x AA batteries would have worked just as well) and a 220Ω resistor. Resistor voltage and power ratings aren’t important for this example, any ~200Ωish resistor will do. I like the battery holders with a builtin power switch. The type of LED shown here are 5mm through-hole (THT). Should be pretty common in electronics/hobby shops. They might even have these at RadioShack/The Source.

Connect One LED

This is how I would connect a single LED to something. The white plastic rectangle is a full-sized breadboard. It allows quick electrical connections without the need to solder or mess with alligator clips or electrical tape. Great for testing and experiments. Using just regular AA batteries and simple components, don’t be afraid to just connect things and see what they do. You won’t do too much damage. Maybe just don’t short the positive and negative of the battery together and continue to hold it in your hand. If you do want to short a battery, do so and toss it away from yourself.

  • POSITIVE of battery goes to POSITIVE of LED
  • NEGATIVE of LED to one end of resistor
  • Other end of resistor to NEGATIVE of battery

Connect Multiple LEDs

Connect Multiple LEDs in Series

I think most common strings of battery powered LED Christmas lights are wired this way with multiple LEDs connected in series with a single resistor. You may need to increase voltage or lower resistance depending on how many LEDs you’re connecting together. If one LED burns out, none of the other ones will light up.

  • POSITIVE of battery goes to POSITIVE of Green LED
  • NEGATIVE of Green LED to POSITIVE of Red LED
  • NEGATIVE of Red LED to one end of resistor
  • Other end of resistor to NEGATIVE of battery
Connect Multiple LEDs in Parallel with Separate Power Connections


This is the most robust way to wire multiple LEDs together. Individual burnt LED or resistor won’t affect the lighting of the others. Also make note of the brightness of the two LEDs compared to the previous connection where they were connected in series. If space and budget allows, this is what I would do for my projects where appropriate.

  • POSITIVE of battery goes to POSITIVE of Green LED
  • NEGATIVE of Green LED to one end of resistor #1
  • Other end of resistor #1 to NEGATIVE of battery
  • POSITIVE of battery goes to POSITIVE of Red LED
  • NEGATIVE of Red LED to one end of resistor #2
  • Other end of resistor #2 to NEGATIVE of battery
Connect Multiple LEDs in Parallel with Shared Power Connection

  • POSITIVE of battery goes to POSITIVE of Green LED
  • NEGATIVE of Green LED to one end of resistor
  • Other end of resistor to NEGATIVE of battery
  • POSITIVE of battery goes to POSITIVE of Red LED
  • NEGATIVE of Red LED to one end of resistor
  • Other end of resistor to NEGATIVE of battery

This is a middle ground between redundant everything and space constraints. As you can see, there are multiple ways to achieve the same end result (lit LEDs in this case).

There are many more related topics that you can dive deeper into, but this should get you started with LEDs and electronics in general. Enjoy!

Battery Cover for Crystal IS33 Pressure Calibrator

I see quite a lot of Crystal IS33 pressure calibrators from customers with broken or missing battery covers and so I thought I would try my hand at 3D printing since I’ve never done it before and the idea of it sounded VERY interesting to me.

Precise measurement is very important when designing something so small. The little tabs that always break are under 1mm thick. Luckily, you can get a decent enough digital caliper for not too much money at Canadian Tire or Princess Auto.

Battery Cover for Crystal IS33 Prototype

I started with measurement of the large basic rectangle shape and then measured the dimensions and position of the four little tabs that holds the battery cover in place. I tried to incorporate the small intricacies of a trapezoid shape of the little tabs, but that was reduced to a simple rectangular prism in the final version. Between the second and third attempt, I added channels on the underside of the battery cover to allow clearance for the two screw holes. I’ve always thought that the grip ribs were on the wrong side of the battery cover for opening, so I moved it to the other side.

Overall, it took three attempts to get a working battery cover that fits the IS33 pressure calibrator perfectly. Not bad for my first experience with 3D printing I think.

3D Printed Battery Cover for Crystal IS33

How to Use the Sunny 16 Rule

Aperture f/16 use shutter speed of 1 over ISO on a bright sunny day, that’s the basic jist of the Sunny 16 Rule.

Conditions Settings
Sunny ISO 100 f/16 1/100s
Slight Overcast ISO 100 f/11 1/100s
Overcast ISO 100 f/8 1/100s
Heavy Overcast ISO 100 f/5.6 1/100s
Shade ISO 100 f/4 1/100s

Back in the day, camera lenses had clicky aperture stops and the Sunny 16 Rule corresponds to these stops.
The common aperture stops were f/1.0, f/1.4, f/2.0, f/2.8, f/5.6, f/8, f/11, f/16 and f/22.
We need to compensate 1 stop for each change in light conditions. Bright sunny conditions have sharp, well defined
shadows. Slight overcast has soft shadows and overcast barely has any shadows from the Sun. Compensate 1 stop for
backlit or snowy (bright white) situations.

I shoot my Canon 6D DSLR like I shoot slide and still use the Sunny 16 Rule. To keep shutter speed up and lens sharp,
my most commonly used settings are based on ISO 200 f/8 1/800s.