Electrical transmission or interconnection systems – Personnel safety or limit control features – Interlock
Patent
1981-09-03
1983-10-04
Zazworsky, John
Electrical transmission or interconnection systems
Personnel safety or limit control features
Interlock
307290, 307299B, H03K 3295, H03K 5153
Patent
active
044081324
ABSTRACT:
First and second transistors which form a differential amplifier have their common emitter connected to a first constant current source and their collectors connected through a current mirror circuit to a power supply. The base potential of the first transistor depends on the current from the input signal source which may vary and which is supplied to the base of the first transistor. The base potential of the second transistor is determined by two resistors and a bias voltage source of a potential difference detecting circuit and by a second constant current source, said resistors, bias voltage source (VBY) and second constant current source being connected to the base of the second transistor. The differential amplifier is therefore turned on or off by the voltage level which is determined by the difference between the base potentials of the first and second transistors, i.e., the current ratio between the first and second constant current sources. Even with gradual increase of the variable current from the input signal source, an "off" state is maintained while the voltage .DELTA.VBE is .DELTA.VBE>O, but is changed to an "on" state when a predetermined current value is reached at which .DELTA.VBE <O. Since a third transistor for current control and a fourth transistor for positive feedback are coupled to the second transistor, the working current thereof is suddenly increased at this time to a constant value which is held steady. This working current is supplied through a fifth transistor for output derivation to a load circuit. With gradual decrease of the variable current of the input signal source in this "on" state, this state is maintained while .DELTA.VBE is .DELTA.VBE <O, but is changed to the "off" state when a predetermined current is reached which is lower than the aforementioned predetermined current and at which .DELTA.VBE becomes .DELTA.VBE>O. At this time, the working current is suddenly reduced to zero due to the positive feedback action of the fourth transistor. Thus, it is possible to supply an output current which has a hysteresis characteristic to the load circuit.
REFERENCES:
patent: 3628059 (1970-06-01), Niu
patent: 3700921 (1972-10-01), Gay
patent: 4013898 (1977-03-01), Makino
patent: 4259601 (1981-03-01), Stein
Tokyo Shibaura Denki Kabushiki Kaisha
Zazworsky John
LandOfFree
Hysteresis circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Hysteresis circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hysteresis circuit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-975828