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    Teaching and game playing machine
    5.
    发明授权
    Teaching and game playing machine 失效
    教学与游戏机

    公开(公告)号：US3629956A

    公开(公告)日：1971-12-28

    申请号：US3629956D

    申请日：1970-08-04

    Applicant: RCA CORP

    Inventor： THOMAS LUCIUS PONDER ,  MCDONALD JAMES ALEXANDER ,  JANSON EUGENE ERNST ,  CHRISTOPHER TODD J ,  PEER JOHN CHARLES

    IPC: G09B7/08

    CPC classification number: G09B7/08

    Abstract: Frames on a film may contain multiple choice questions which can be answered by selecting one of a number of answer buttons but each frame includes only a single next address code. The latter has only a small number of bits but is ambiguous in the sense that the present address on a number of frames is equal to this next address. The ambiguity is resolved by counting the frames having this common present address until the one called for by the selected answer button is reached. A second feature of the machine useful in playing games is the production of a random number in response to a user actuated button for comparison with the count of frames having a particular common present address.

    Astable multivibrator circuit with means for ensuring proper starting of oscillations
    6.
    发明授权
    Astable multivibrator circuit with means for ensuring proper starting of oscillations 失效
    用于确保振荡正常启动的手段的多功能多功能电路

    公开(公告)号：US3688154A

    公开(公告)日：1972-08-29

    申请号：US3688154D

    申请日：1970-05-11

    Applicant: RCA CORP

    Inventor： CHRISTOPHER TODD J

    IPC: H03K3/26 ,  H03K4/64 ,  H04N3/18 ,  H03K3/282 ,  H01J29/70

    CPC classification number: H03K3/26 ,  H03K4/64 ,  H04N3/18 ,  Y10T307/747 ,  Y10T307/983

    Abstract: In an astable multivibrator circuit, a diode operates in conjunction with a voltage supply derived from the multivibrator output signal to insure the initiation of oscillations by limiting base drive current to the multivibrator transistors when power is first applied. This prevents saturation of both transistors and ensures sufficient loop gain to initiate oscillations in response to an unbalance in the system. As power is first applied, the diode is non-conductive and a relatively low voltage is applied to bias the multivibrator transistors. During normal operation, the voltage derived from the multivibrator output signal causes the diode to conduct, thereby coupling the base circuits to the operating potential supply. While conductive, the diode forward voltage drop compensates for changes in the Vbe of the transistors due to temperature variations and tends to maintain a constant charging current for the base circuits.

    Abstract translation: 在不稳定的多谐振荡器电路中，二极管与源自多谐振荡器输出信号的电压源一起工作，以在首次施加电源时将基极驱动电流限制在多谐振荡器晶体管上，以确保振荡的起始。 这可以防止两个晶体管的饱和，并确保响应于系统中的不平衡而产生振荡的足够的环路增益。 当电源首次施加时，二极管是不导通的，施加相对较低的电压以偏置多谐振荡器晶体管。 在正常工作期间，由多谐振荡器输出信号导出的电压导致二极管导通，从而将基极耦合到工作电位。 导通时，由于温度变化，二极管正向压降会补偿晶体管的Vbe变化，并且趋向于为基极电路保持恒定的充电电流。

    Frequency controlled oscillator
    8.
    发明授权
    Frequency controlled oscillator 失效
    频率控制振荡器

    公开(公告)号：US3611176A

    公开(公告)日：1971-10-05

    申请号：US3611176D

    申请日：1970-07-31

    Applicant: RCA CORP

    Inventor： CHRISTOPHER TODD J

    IPC: H03K3/0231 ,  H03K4/06 ,  H03K4/501 ,  H03K3/282

    CPC classification number: H03K3/0231 ,  H03K4/06 ,  H03K4/501

    Abstract: An oscillator circuit employs first and second emitter coupled transistors in a switch configuration. First and second trip voltages are developed by a voltage divider network in conjunction with a third transistor and are applied to the base of the second transistor. The third transistor regeneratively aids in switching conduction states of the second transistor and changes the trip voltage applied to the base of the second transistor as well as in the input signal to an integration network coupled to the base of the first transistor to sustain oscillations. Frequency control is effected by coupling the collector-to-emitter current path of a fourth transistor in parallel with the collector-to-emitter current path of the second transistor. An automatic frequency control (AFC) voltage is applied to the base of the fourth transistor to cause the second and third transistors to switch in response to the AFC control signal instead of the fixed lower trip voltage, thereby varying the frequency oscillation of the circuit.

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