Home Computer - Lerncomputer ZX81
Sinclair Radionics Ltd.; St. Ives (Cambridge)
- Produttore / Marca
- Sinclair Radionics Ltd.; St. Ives (Cambridge)
- Anno
- 1981–1984
- Categoria
- Elaborazione di segnali e strumenti di calcolo (Computer e moduli SP)
- Radiomuseum.org ID
- 361060
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- Numero di transistor
- A semiconduttori.
- Gamme d'onda
- - senza
- Tensioni di funzionamento
- Fornita mediante altra unità o unità principale. / DC 9 Volt
- Altoparlante
- - Per cuffie o amplificatori esterni
- Materiali
- Plastica (non bachelite o catalina)
- Radiomuseum.org
- Modello: Home Computer - Lerncomputer ZX81 - Sinclair Radionics Ltd.; St.
- Forma
- Tascabile (portatile molto piccola), < 20 cm
- Dimensioni (LxAxP)
- 167 x 167 x 40 mm / 6.6 x 6.6 x 1.6 inch
- Annotazioni
-
The Sinclair ZX81, launched in March 1981, transformed home computing as an affordable, mass-produced device designed by Sinclair Research and manufactured by Timex in Scotland. Priced at £49.95 (kit) or £69.95 (preassembled), it sold over 1.5 million units, becoming the first widely accessible computer in UK high-street stores like W.H. Smith. Its streamlined design used just four chips and 1 KB of RAM (expandable to 16 KB), with a membrane keyboard and TV display. In the U.S., Timex rebranded it as the ZX-81, later releasing upgraded models. The ZX81 catalyzed Britain’s tech industry, fostering a community of enthusiasts and earning its designer, Rick Dickinson, a Design Council award. Its success solidified Sinclair Research’s reputation and contributed to Clive Sinclair’s knighthood.
Sinclair ZX81 Technical Overview
Single-board architecture with four primary components: Z80 CPU, ULA2C184E logic chip, 8 KB ROM, and 1 KB RAM.Processor
- CPU: Z80 @ 3.25 MHz (NEC uPD780C variant in some units)
- Effective speed:
- SLOW mode (display active): 0.8 MHz (50Hz) / 0.53 MHz (60Hz)
- FAST mode (display disabled): Full 3.25 MHz
Memory
- ROM: 8 KB (BASIC interpreter with floating-point math and 30+ functions)
- RAM: 1 KB base (expandable to 16 KB via edge connector, third-party expansions up to 64 KB)
- Note: Timex variants like TS1000 included 2 KB RAM
Video Output
- ULA2C184E generates 256×192 pixel output (32×24 characters)
- RF modulator: UM1233 chip for UHF 625-line TV output
- Display modes:
- Text: 32×24 characters (8×8 pixels per char)
- Block graphics: 64×48 elements (4×4 pixels per block)
Storage & I/O
- Cassette interface: 3.5mm jacks for audio storage (300 baud)
- Expansion port: 44-pin edge connector for RAM/ROM cartridges
Keyboard
- Membrane layout: QWERTY with 20 graphic/54 inverse video characters
- Multi-function keys: 5 roles per key via shift combinations
- Modern add-ons: ZX-Key interface enables USB/emulator compatibility
Pricing & Variants
- US launch: $99.95 (kit) / $149.95 (assembled, Nov 1981)
- German price: 398 DM assembled
- Timex models: TS1000 (2 KB RAM), TS1500 (16 KB integrated)
Operating System
- Sinclair BASIC: Includes trigonometric functions (8-digit precision) and RND/RAND operators
Legacy Issues
- Crash susceptibility: Loose RAM pack connections caused frequent data loss
- ULA failures: Modern replacements are scarce due to custom chip design
Note on RAM claims: While some sources mention 2-3 KB configurations, standard UK models shipped with 1 KB. Higher capacities required aftermarket expansions.
- Peso netto
- 0.342 kg / 0 lb 12.1 oz (0.753 lb)
- Prezzo nel primo anno
- 69.95 £
- Bibliografia
- -- Original-techn. papers.
- Letteratura / Schemi (1)
- Funkschau (Sonderheft Nr. 08, "ZX81 Kochbuch")
- Autore
- Modello inviato da Alfred Klich. Utilizzare "Proponi modifica" per inviare ulteriori dati.
- Altri modelli
-
In questo link sono elencati 43 modelli, di cui 41 con immagini e 20 con schemi.
Elenco delle radio e altri apparecchi della Sinclair Radionics Ltd.; St. Ives (Cambridge)
Collezioni
Il modello Home Computer - Lerncomputer fa parte delle collezioni dei seguenti membri.