One AA battery inside the Walkman. Usually directly accessible on the outside, sometimes under the cassette.
Two AA batteries inside the Walkman. Usually directly accessible on the outside, sometimes under the cassette.
Four AA batteries inside, usually in some kind of holder. Sony also used it in the portable DAT range.
External compartment for 1*AA battery. Usually has a DC in jack to power the device, not to charge the battery
External compartment for 1*C (r14) battery.
External compartment for 2*AA batteries.
External compartment for 2*AAA batteries. Some Aiwa sidecars have 2V DC in jack.
External compartment for 2*D batteries, like the Sony EBP-500
Rechargeable rectangular battery (NiCd/NiMH)
dim.: 67x17x6.1 mm.
Voltage: 1.2 V
Rechargeable rectangular battery (Lead-Acid), in different variants. Sometimes contacts are on top (logo side), sometimes on end.
dim.: 68x17x6 mm.
Voltage: 2 V