JPS622742Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a plunger operating circuit that prevents malfunctions.

In general, a plunger, as shown in Fig. 1, involves winding a coil 2 around a core 1, attracting an iron piece 3 using the magnetism generated by passing a current through the coil 2, and operating a lever 4 to put the tape recorder into playback mode. etc. is being done. In such a plunger, there is a problem in that if the current flowing through the coil 2 is simply interrupted to release the iron piece 3, a magnetic loop as shown by the dashed line is created, and the iron piece 3 cannot be released. A countermeasure against this problem is to provide a gap to prevent the formation of a magnetic loop, but if a gap is provided, the attraction force will be reduced. Furthermore, by passing a small current in the opposite direction, the magnetic loop can be canceled out and easily released, but conventionally a separate coil has been provided for this purpose, which has complicated the circuit and configuration.

The present invention provides a plunger operating circuit which eliminates such drawbacks, and will be explained below with reference to the drawings.

5 is a power supply, 6 is a diode 7 connected in series between the power supply 5, a plunger coil 8 and a transistor 9.
The diode 7 is connected in the forward direction to the power supply 5, and the transistor 9
A switch 10 that is linked to a playback button (not shown) is connected to the base. 11 has one end connected to power supply 5
a first resistor whose other end is connected to the connection point 12 between the plunger coil 8 and the transistor 9;
It has a sufficiently large resistance value compared to the forward resistance value of the diode 7. 13 is a second resistor whose one end is connected to the connection point 14 between the diode 7 and the plunger coil 8 and the other end is connected to the ground electrode which becomes the common electrode of the power source 5;
has a resistance value greater than the resistance value of .

Next, the operation of the present invention will be explained. First, when the playback button is pressed, the switch 10 is turned on, and the transistor 9 is also turned on. Then, the current from the power supply 5 flows through the diode 7, the plunger coil 8, and the collector-emitter of the transistor 9, so that the plunger coil 8 is energized, attracts the iron piece 3, and puts the tape recorder into a reproducing state.

When the reproduction is completed and the switch 10 is turned off, the transistor 9 is also turned off. Then diode 7
is turned off, this time the current from the power source 5 flows through the first resistor 11 from the bottom to the top of the plunger coil 8, and then returns to the power source 5 through the second resistor 13. Therefore, a current flows through the plunger coil 8 in the opposite direction to that when the switch 10 is turned on, so that the magnetic loop formed between the plunger coil 8 and the iron piece is canceled out, and the attraction force to the iron piece is released. The iron piece is separated from the core by the force of a spring or the like.

As mentioned above, the plunger operating circuit of the present invention has the following features:
When the transistor connected in series to the plunger coil is turned on, a large forward current flows through the plunger coil, which excites the plunger coil and attracts the piece of iron, and when the transistor is turned off, the plunger coil A small current flows in the reverse direction to cancel the magnetic loop, so
The plunger can be easily rendered inoperative.

[Brief explanation of drawings]

Figure 1 is a side view of a general plunger device, Figure 2
The figure is an operational circuit diagram of the plunger of the present invention. 5... Power supply, 6... Series circuit, 7... Diode, 8... Plunger coil, 9... Transistor, 11... First resistor, 13... Second resistor.

Claims (1)

[Scope of utility model registration request] A series circuit consisting of a diode, a plunger coil, and a transistor connected in series between both ends of a power source in a forward direction with respect to the power source, a switch for turning the transistor on and off, and one end connecting the power source and the diode. a first resistor connected to the point and the other end connected to the connection point between the plunger coil and the transistor, one end connected to the connection point between the diode and the plunger coil, and the other end connected to a ground electrode that is a common power source. and a second resistor.