Power Coins

The Power Coins were supernatural golden coins, created by Ninjor, which were used as the power source of the original Power Rangers.

Dinosaur Coins
The original Coins drew their power from the ancient dinosaurs and had an animal engraved on each one: Mastodon, Pterodactyl, Triceratops, Saber-Toothed Tiger, and Tyrannosaurus. The sixth Coin was based off a dragon, but instead had a symbol resembling a dragon's footprint. Zordon gained possession of the first five coins after he and Alpha 4 found a map that lead them to the location of the coins in the Desert of Despair. Unfortunately, Rita Repulsa somehow gained the Dragon Coin.

The Rangers could remove their coins and transform them into Power Crystals. The holder places his thumb and index fingers on the edge of the Coin, heads facing out. The individual then elongates the crystal down to a point. The Rangers usually shout "Two-One-Power Up", and insert it into a slot on the helm of his/her Zord in order to control the war machines.

The Coins can also emit powerful energy charges which have been used to re-energize Zordon.

When Tommy Oliver's Green Ranger powers were permanently drained by Lord Zedd's Green Crystal, Zordon and Alpha secretly created the White Ranger, using the White Tiger Coin as his power source. Whether Zordon created this Coin or had it from the beginning is unknown.

In the beginning of Season Three, Rito Revolto, brother of the vile Rita, appeared in the Moon Palace. Leading an army of monsters, he successfully overloaded the Thunderzords' power storage, shorting out several Command Center functions, destroying the Thunderzords, and damaging the Rangers' Power Coins and their connections to the Morphing Grid.

During Power Rangers In Space, Adam Park returned, attempting to help his successor, Carlos Vallerte, overcome a confidence issue after a botched mission. When Carlos decided to hang up his morpher, Adam pulled his damaged morpher out. Despite Alpha 6's attempts to stop him, he successfully morphed into the Black Mastodon Ranger once more. However, due to the damage the coin sustained during the fight with Rito Revolto, the unstable connection to the Morphin Grid caused Adam to phase in and out of a morphed state, causing him great pain, and nearly destroying him.

Several years later, during the events of Operation Overdrive, Adam's morpher and Mastodon coin were restored by the Sentinel Knight.

Power Crystals
Whenever one Ranger was in great peril, and the others would need to assist them, Rangers could put their hands together and form a power crystal out of their morphing essence (their coin). With it, they could transport themselves to wherever their crystals were if a Ranger activates them. The Crystals could be transported through the morphing grid to a Ranger's Power Weapon, first seen in A Pressing Engagement. When Jason had his (Red) along with the other four, he could activate them, transporting his friends Kimberly (Pink), Zack (Black), Billy (Blue), and Trini (Yellow) to his location. The Rangers become beams of colored light upon transport. They could also be used in conjunction with the Dinozords, projecting energy from all 5 Zords at once in the Megazord's Tank Mode, or one concentrated blast in Battle Mode.

Ninja Coins
With the loss of their powers, Zordon sends the Rangers to find the minter of the Power Coins, the mysterious sage Ninjor. After proving themselves, Ninjor creates six new Coins which draw on the power of six animal spirits that represent each ranger. With the new coins and powers, the Rangers receive the power of the Ninja along with new Ninjazords.

Unlike the Dino Coins, the Ninja Power Coins draw on the lifeforce of each respective Rangers. This proved to be dangerous when Rita and Zedd were successful in stealing Kimberly's Crane Power Coin thanks to the help of their brainwashed Katherine. But the Power Coin is later returned to Kimberly. In A Different Shade of Pink, after a 10-episode story arc concerning her, Kimberly retires and gives her Crane Coin to a reformed Katherine Hillard.

When Master Vile uses the Orb of Doom to reverse time on Earth, the Rangers become powerless kids. With help from Billy, Cestro creates a regenerator using the Ninja Coins as a power source. However, only Billy returns to his true age before the device is destroyed by Rito and Goldar. Goldar and Rito teleport into town, and chase after the kids. They manage to steal their coins, and bring them to Zedd and Rita. Firing blasts from their staffs, the Ninja Coins are destroyed in Goldar's hands.

Despite this, it appears the Ninja Coins are in some form bonded to the Rangers' on a spiritual level. Tommy, Kat, and Adam are all guided by their respective Ninja animal spirits on their quests for the Zeo Sub-Crystals. Even after becoming the Red Zeo Ranger, Tommy would be guided by the spirit of the Falcon during his vision quest, ultimately leading him to his long lost brother. Though not canon with the show, in the film, Dulcea provides an explanation: "Within each of us is an animal spirit waiting to be released."

Alien Coins
The Aquitian Rangers were given Power Coins by Ninjor 1000 years ago, though it is unknown if he granted them the ability to morph into Power Rangers or even when the Aquitian Rangers received the power. Unlike the others, the Aquitans seemed to draw power directly from their Coins to morph. They did not have a morpher.

Trivia

 * The Morphers and Dino Coins used in the show are actually the toy Dino Bucklers from the Super Sentai series Kyoryu Sentai Zyuranger. Using the toys as props would soon become a tradition.