Device for generating a control signal dependent on a variable resistance value and apparatus comprising such device
First Claim
1. A device for generating a control signal voltage (Uc) by producing a current through a variable resistor (8), the control signal voltage being dependent on the resistance value of the variable resistor (8);
- said device comprising;
a transformer (24) having a first winding (22) and a second winding (26);
a rectifier diode (20) in series with the first winding (22);
means for connecting the variable resistor (8) in series with the first winding (22) and the rectifier diode (20) so as to form a closed loop for current flow therein in one direction;
a current generator (32) coupled to the second winding (26) to supply thereto a periodically interrupted current (I2), each interruption thereof inducing a voltage across the first winding (22) which renders said rectifier diode (20) conductive and produces a current flow in said loop through the first winding (22) and the variable resistor (8), said induced voltage having a peak value dependent on the resistance value of the variable resistor (8); and
a peak detector (62) for detecting the peak value of the voltage produced across the first winding (22) upon each interruption of the current (I2) in the second winding (26), said detected peak value constituting the control signal voltage (Uc).
1 Assignment
0 Petitions
Accused Products
Abstract
A device for generating a control signal voltage which is dependent on a resistance value of a variable resistor (8) includes a transformer (24) having a first winding (22) which is in series with the variable resistor and a rectifier diode (20). A current generator (32) coupled to a power source is coupled to a second winding (26) of the transformer and supplies it with a periodically interrupted current (I2). Upon each such interruption an exponentially decreasing current will flow through the first winding and also through the variable resistor (8). The peak value of the voltage drop produced by such current across that resistor is proportional to the resistance value thereof. It is also produced across the first winding (22) and is detected by the peak detector (62). That constitutes the control voltage (Uc). Since the variable resistor is fully electrically isolated from the power source, it can be safely touched without shock hazard.
-
Citations
36 Claims
-
1. A device for generating a control signal voltage (Uc) by producing a current through a variable resistor (8), the control signal voltage being dependent on the resistance value of the variable resistor (8);
- said device comprising;
a transformer (24) having a first winding (22) and a second winding (26); a rectifier diode (20) in series with the first winding (22); means for connecting the variable resistor (8) in series with the first winding (22) and the rectifier diode (20) so as to form a closed loop for current flow therein in one direction; a current generator (32) coupled to the second winding (26) to supply thereto a periodically interrupted current (I2), each interruption thereof inducing a voltage across the first winding (22) which renders said rectifier diode (20) conductive and produces a current flow in said loop through the first winding (22) and the variable resistor (8), said induced voltage having a peak value dependent on the resistance value of the variable resistor (8); and a peak detector (62) for detecting the peak value of the voltage produced across the first winding (22) upon each interruption of the current (I2) in the second winding (26), said detected peak value constituting the control signal voltage (Uc). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
- said device comprising;
Specification