Commodore SR - 4148R Calculator, USB Lith. Battery Charging, Uncorroded
Item History & Price
| Reference Number: Avaluer:55804896 | Period: 1974 |
| Country/Region of Manufacture: United Kingdom | Modified Item: No |
This calculator is the 'classic' ( ergonomic ) model which has only one operation for each button ( except for the arc button! ). It is regarded as a rugged model and has one of the brightest red led displays. Fortunately, this one now has replaceable AAA Lithium batteries ( in a plastic box ) inside which have about 30 percent more capacity than the original AA NiCad batteries. This means that they should last a good three hours instead of the two hours with the old N...iCad batteries, and leakage corrosion is less of a threat. Any leakage from modern Lithium batteries is far less corrosive than what always came out of old Nicad batteries. Replacing the batteries ( say every couple of years ) is just a matter of removing two screws to open the case, and the excellent batteries used now cost less than a pound each ( on Amazon ). The only sign that this calculator has been updated is the absence of a charging brick, which after 47 years may not be in the best of health when it comes to insulation etc. and probably should not be used unattended.The chip used in the charging circuit is one used in many rechargeable items which are on the market. It has a blinking red LED when not connected, a steady light when charging and a flashing light ( slower than blinking ) when the batteries are fully charged after the circuit has steadily reduced the current and then stopped it.The charger can be used with any standard USB power supply, including a PC port, and supplies a current which is regulated to protect the batteries. It is not intended for use with proprietary USB fast chargers, especially ones producing a varying high voltage.The old original ( steady ) 6volt adaptor can no longer be used. Only a regulated 4.2 volt supply can now be used which protects the new Lithium batteries from damage.
The Commodore SR4148R is a scientific calculator with 10 digits precision and algebraic logic. It has 30 functions, 48 keys, and an LED (light-emitting diode) display, typical of calculators of this era. The power source is 'sealed'.Facts at a glance:FeatureValueTypeScientificFunctions30Keys48Precision10LogicAlgebraicDisplay typeLEDLength152mmWidth81mmThickness30mmWeight158gPower Consumption1.500000WPower SourceSealedCountryUSA & UKYear introduced1974Year discontinued1975
The Commodore SR4148R is a scientific calculator with 10 digits precision and algebraic logic. It has 30 functions, 48 keys, and an LED (light-emitting diode) display, typical of calculators of this era. The power source is 'sealed'.Facts at a glance:FeatureValueTypeScientificFunctions30Keys48Precision10LogicAlgebraicDisplay typeLEDLength152mmWidth81mmThickness30mmWeight158gPower Consumption1.500000WPower SourceSealedCountryUSA & UKYear introduced1974Year discontinued1975
