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Calculators: Handheld: Citizen Eight
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Size (approx): |
64mm
x 100mm (104mm with tag) x 22mm (w,h,d) Weight 84g excluding batteries. |
| Power: | 4.5V DC, 3 x AAA size batteries, 0.15W. It does not accept an adapter. | ||
| Case: | Two piece case in matt dark and light grey plastic. Above the display is a small silver painted recess with raised logo. The green plastic display filter is flat, flush and wraps around either side. Below this is a small metallic label in its own recess printed black with the brand and model name. The keyboard surround is brushed aluminium with a thin dark grey plastic border. The keys are springy, slightly wobbly and have a soft metallic click. There is a small plastic tag on the top edge, to the left, for a carry strap. | ||
| Display: | 8 digit green VFD with a ninth digit for negative and error indication. | ||
| Features: | Standard four functions with percentages. | ||
| Age: | 1976 | ||
| Manufacturer: | Citizen Business Machines Inc., made in Japan. serial number 540941 on a label on the battery compartment cover. | ||
| Comments: | Very compact palm-sized handbag market calculator. The only odd thing is that it appears to use standard-size calculator keys - which look too big. The logic is very poor with lack of recovery, numerous negative zero bugs and the pseudo fixed decimal bug. The original case is soft brown plastic with open top and deep half-moon cut-outs either side. It has prominent external red stitching and Citizen embossed on the front. |
| Components: | 1 x cpu: Toshiba T3332 51, 28
pin DIL 0.6" width black plastic 1 x 9 digit VFD single tube flat face: Futaba 9-ST-20 5I (date code September 1975) 2 x transistors 3 x diodes 6 x capacitors 3 x resistors 1 x transformer: 05 |
| Boards: | The keyboard assembly (GK-195-1 GICO Japan 50.11.10) (date code 10th November 1975) is attached to the very compact main board (80-Ea) with 12 strong short wires. |
| Construction: | Remove the single screw from the rear and the front or back will lift away easily, hinging from the bottom edge. The battery compartment is connected to the keyboard assembly board by two large springy metal tabs. |
| Logic comments: | The (CE) key is used to cancel an entry and (C) clears the whole calculator |
| Overflow on the input of a number is suppressed: keying in a ninth digit is ignored | |
| There is automatic constant on multiply and divide only | |
| Negative numbers are flagged by a "-" sign in the far left (ninth) digit thereby allowing full eight digit negative numbers | |
| Overflow shows the result with “E” in the far left (ninth) digit and is not recoverable | |
| A divide by zero shows zero and “E” in the far left (ninth) digit and is not recoverable | |
| The percentage key just divides by 100, repeatedly; even zero is divided to make “0.00” | |
| It suffers the pseudo fixed decimal bug: key in (1)(+)(.)(0)(0)(0)(=) to give “1.000” which will remain a fixed three digit decimal number until you need more digits or use multiply or divide | |
| It also suffers the divide to minus zero bug: key in (1)(-)(=) to give “-1” then (/)(1)(0)(=)(=)(=) etc to eventually give “-0.0000000” |
