Electronic control circuit for the drive motor of a magnetic sound device
US3952330A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 5, 1974 |
| Grant date | Apr 20, 1976 |
| Priority date | — |
| Expiry date | Dec 5, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P3/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electronic control circuit is provided for a magnetic sound device of the type having a sound recording medium transport, a direct current drive motor for the transport, a main control switch, andd a circuit interconnecting the motor to a direct current power supply through the main control switch in accordance with a first polarity and an audio circuit. The present circuit comprises an auxiliary control switch interposed between the motor and main switch and a switch circuit including first and second transistor switches connected between the main control switch and motor for reversing the polarity of the interconnection between the power supply and motor. A capacitor is interconnected between the motor and the transistor switches for activating the transistor switches during the charge-up time of the capacitor when the auxiliary switch is open. The present circuit further shorts out the audio circuit for a brief time period after the auxiliary switch is opened or closed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.