US3728496A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thin film transistor phonograph amplifier
Assignee: Westinghouse Electric Corp
•
Filing: 1970-05-05
•
Granted: 1973-04-17
•
Expires: 1990-05-05
Abstract
Abstract This disclosure relates to an electrical circuit for conducting a signal from a high impedance ceramic pick-up cartridge, as is used in a phonograph, to a thin film field effect transistor and then to a speaker via a matching transformer. If desired, two thin film field effect transistors may be used and the signal fed directly to a speaker without employing a matching transformer.
Inventors
- 👤 D Page
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:45
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/181; H03F3/183; H03F3/185; H03F3/1855; H10; H10D; H10D99/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
96 words
An amplifier circuit consisting of power supply terminals, a thin film field effect transistor, a speaker, means for matching the impedance of the transistor with the impedance of the speaker and a high impedance pick-up cartridge, the transistor, and impedance matching means with the speaker coupled thereto being connected in a series circuit relationship between said power terminals, said pick-up cartridge having a first terminal connected to a gate contact of the transistor and a second contact connected to a common terminal with a source contact of the transistor and one of the power supply terminals.
Claim 2
Dependent Claim
96 words
An amplifier circuit consisting of power supply terminals, a thin film field effect transistor, a speaker, means for matching the impedance of the transistor with the impedance of the speaker and a high impedance pick-up cartridge, the transistor, and impedance matching means with the speaker coupled thereto being connected in a series circuit relationship between said power terminals, said pick-up cartridge having a first terminal connected to a gate contact of the transistor and a second contact connected to a common terminal with a source contact of the transistor and one of the power supply terminals.
Claim 3
Dependent Claim
30 words
The circuit of claim 1 in which the means for matching the impedance of the transistor with the impedance of the speaker is a power, thin film, field effect transistor.
Claim 4
Dependent Claim
22 words
The circuit of claim 1 in which a variable resistor is connected in series with the source contact and the common terminal.
Claim 5
Dependent Claim
26 words
The circuit of claim 1 in which the means for matching the impedance of the transistor with the impedance of the speaker is a matching transformer.
Claim 6
Dependent Claim
22 words
The circuit of claim 4 in which a variable resistor is connected in series between the matching transformer and power supply terminal.
References Cited (Backward Citations)
GB1086812A
Cited
US3512100A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |