Sound, light, heatRebuild shelfHand tools, works as-is

Small solar cell

Also called garden light cell, calculator cell, photovoltaic.

The cell from a garden light is usually a few square centimetres and about 2 V open-circuit in sun, sized to charge one NiMH cell through the chip. Calculator cells are lower current and more fragile. Neither will run a motor directly in any useful way.

If you are new to this category

Speakers, lamps, heaters, and displays. To test a speaker, touch a 1.5 V cell to the terminals for a moment. The cone should click once. A heater can start a fire if you remove the part that was supposed to shut it off.

Heat and bright light usually mean household voltage. Unplug first. If the original safety part is open, find out why before you replace it.

The one-second speaker test

Touch a 1.5 volt cell to the two terminals for a moment only. A good cone clicks and moves. A scrape means the coil is rubbing, which will sound bad even if it still makes noise. The ohms printed on the magnet, often 4, 6, or 8, tell you what amplifier it expects.

Specification. The right-hand column is what is typical. The label on the part in your hand wins if they disagree.
What to look for	Usual figure
Garden	About 2 V open circuit, tens of mA in full sun. Indoor light collapses that.
Night	The same chip that boosts the LED also detects dark. A bare cell does not.

Volts are electrical pressure, amps are how much current is flowing, and ohms are how hard the part resists that flow. A higher voltage than the part was built for is how salvage parts die on the bench. If a cell in the table says “read the stamp”, that stamp is the whole specification.

What people actually use it for

A garden light rebuild
A day/night sense
A trickle into a small cell with a real charge path

Leave this one when

The epoxy is crazed and white. Output is already gone.

Buying a new one is the better idea when

A panel with a wattage, once the load is more than an LED.

How to tell if this one still works

In sun, open-circuit voltage, then short-circuit current on the mA range. That pair is the whole datasheet.

Tools you will want: Meter, Sun.

Words on this page

Short meanings, so the rest of the entry is readable if you are not already doing this every weekend.

datasheet: The manufacturer's document for a part: voltages, pin order, limits. A salvage part with no readable number does not have one you can trust.

Where people actually find it

2 notes, most useful first. “Leave it” means the part is in that machine and you should not take it: it is dangerous, worn out, or only useful if you already know that exact repair.

Harvest at a glance
From	Call	How many	How often	Where it sits
Solar garden light	Prize	1	always	The top.
Motorized toy	Bonus	1	sometimes	Solar toys.

Prize — take this firstSolar garden light1 · always
In this particular machine
About 2 V open circuit in sun, low current.
Where to look
The top.
How to get it out
Desolder gently. The tabs break.
The condition to expect
Crazed epoxy is a weak cell.
Bonus, if you are already in thereMotorized toy1 · sometimes
In this particular machine
Small.
Where to look
Solar toys.
How to get it out
Measure in sun.
The condition to expect
Fine.