1. A probe, comprising:
a conductive plunger received inside a cylindrical conductive barrel in which the plunger being capable of moving backward and forward; and
an urging coil spring for pushing a rear end of the plunger also received inside the barrel so as to urge a front end of the plunger out of an opening at one end of the barrel;
said plunger including a conductive coil spring;
said conductive spring is inserted between an inner circumference of the barrel and an outer circumference of the plunger; and
said conductive spring is provided for stabilizing electrical contact between said barrel and said plunger without urging said plunger.
2. A probe according to claim 1, wherein said conductive coil spring is fixed to an inner wall of said barrel.
3. A probe according to claim 1, wherein said conductive coil spring is provided in the vicinity of the opening at the one end of said barrel.
4. A probe according to claim 1, wherein a central and a rear large-diameter portions are provided;
said central portions is provided substantially at a center in a longitudinal direction of said plunger; and
said rear large-diameter portion is provided towards the rear end of said plunger; and
the rest portion of said plunger is a small-diameter portion having a smaller diameter than these large diameter portions.
5. A probe according to claim 1, wherein two protrusions are disposed so as to respectively protrude towards the center from the inner wall of said barrel, in such a manner that
one is provided inside said barrel towards the side of said open end of said barrel for engaging said conductive coil spring; and
another protrusion is provided in an inner wall in the vicinity of the center in the longitudinal direction of said barrel for engaging a large-diameter portion formed at the side of the rear end of said plunger.
6. A probe according to claim 1, wherein said plunger is formed in the shape of a cylinder; and said cylinder member having V-shaped channels in the front end of said plunger so as to intersect in cruciform for protruding a plurality of points.
7. A probe according to claim 6, wherein terminals of an object to be tested are a ball grid array (BGA).
8. A probe according to claim 1, wherein a portion towards the side of a closed end of said barrel is bent to form a small curved shape as a whole.
9. A probe according to claim 1, wherein, with said conductive coil spring received inside said barrel, one end is disposed at the open end of said barrel, and said conductive coil spring has a length such that the other end is disposed at the same position as the end of said central large-diameter portion when said plunger is moved maximum length out of said barrel.
10. A probe according to claim 9, wherein said conductive coil spring is formed to have a length about \u2153 of the total length of a small-diameter portion disposed at the side of the one end of said plunger.
11. A probe according to claim 1, wherein a projection is formed at the rear end of said plunger, and said projection is inserted inside one end of said urging coil spring.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A system for regulating AC electrical power delivered from a source to a load, the system having:
a voltage regulating device (51) which, in use, is connected at an input side thereof to the source and at an output side thereof to the load, the voltage regulating device being controllable to vary the ratio of the voltage amplitudes at the input side and the output side;
a measuring arrangement (53) for measuring the voltage amplitude, current amplitude and the voltage frequency at the input side; and
a control device (55) for determining a desired ratio of the voltage amplitudes depending on the measured voltage amplitude, the measured voltage frequency and the measured current amplitude;
wherein the control device is adapted to issue an output command to the voltage regulating device, the output command controlling the voltage regulating device to provide the voltage amplitude ratio determined by the control device.
2. A system according to claim 1, wherein the voltage regulating device is a transformer having a variable primary to secondary ratio.
3. A system according to claim 1, wherein the measuring arrangement also measures the power level of the delivered power at the input side control device, and the control device determines the desired voltage amplitude ratio also depending on the measured power level.
4. A system according to claim 1, wherein the control device is further adapted to receive a request signal (54) corresponding to a desired delivered power level to the load, and the control device also determines the desired voltage amplitude ratio depending on the request signal.
5. Use of the system according to claim 1 for regulating AC electrical power delivered from a source to a load.
6. A variable speed generator having the system according to claim 1 for regulating AC electrical power delivered from the generator to a load.
7. An engine ignition unit having the system claim 1 for regulating AC electrical power delivered from a generator to the unit.