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Mar 14, 2010
Experiments with Tubes

Practical acquaintance with the work of radio tubes is best to start with simple experiments with a single lamp. For this purpose it is desirable to make radiokonstruktor - a set of panels with details.

The first of these sets, two pairs of terminals (terminals) to strengthen parts: capacitors and resistors. As the clamps for sheet-metal parts make good use of clips, which, together with the details inserted in the holes the mounting plate. In the second panel reinforced lamp socket. If the experiments will be applied finger lamp, you must make one additional panel with finger lamp sockets. In addition to the panels, this panel are set five times for liner supply. In the third panel design stronger pair of telephone jacks and two clamps.

All experiments with lamps, as described in the book, you can successfully carry out this designer.

Experiment 1.

Electronic lamp as a detector. In the role of the detector crystal set, as we know, does the crystal. Such a crystal detector can be replaced by a tube. The simplest vacuum tube detector is a diode detector. They can serve as a two-electrode vacuum tube battery power. However, for the same purpose can be used and any other multielectrode lamp, for example 2K2M, 2ZH2M, 1KSH, SB-241, 'combining all of its grid (shielding and control) with the anode. Figure 17 shows a schematic diagram of the receiver with the detector tube detector. As seen from the figure, the circuit of the receiver remains the same, only instead of a crystal detector is now worth tubes. To operate the detector tube to food - electric current to the heater tubes. To this end, take a galvanic cell (eg * AP-L-30) and connect it to the respective legs on Lampovo base. But best of all, if the young amateurs will enjoy a special lamp on top, into which is inserted tubes. Then the wires that go to the glow and the anode of the lamp, not soldered to the legs of the cap, and to the jacks on the tube sockets.

To avoid mistakes, which stem from how the conductor is necessary to connect, you need to get acquainted with the pinout of the lamp. Figure 16 shows how the legs are numbered on the pedestal lamp and the lamp socket.   Take the experience of the lamp 2K2M. In order for this lamp include a detector circuit 17 as necessary to the jacks lamp socket 2 and 7 draw current from the elements, nest 3 and 4 and the upper cap of the control grid to connect between a general guide. Then the nest 3 and 2 two conductors are connected to a crystal set. Figure 17, and given the scheme builds on the experience of designer panel. Receiver with a tube detector works just as with the crystal. Radio reception is possible only on the handset.

Experiment 2.

Electronic lamp as an amplifier. To increase the volume of the detector of the receiver, you need power, the main role in which the vacuum tube performs. The simplest amplifier low (sound) frequencies is odnolampovy amplifier. It increases the volume of admission to handsets, but its gain is not enough for the speaker. Only his closest powerful radio station will give a speakerphone device. Schematic diagram of the tube amplifier 2K2M (or 2ZH2M, SB-241, 1KSH) is shown in Figure 17.6. In this scheme, each grid lamp is turned on in different ways. In the chain of control grid (the first of the filament) lamps put resistance R. As seen from the scheme, it is turned parallel to the input jacks of the amplifier, as the load for the detector of the receiver (instead of disabling the handsets) and the leakage resistance of the grid. In this resistance to flow down to the cathode, electrons accumulated on the grid when it is a positive charge.

Shielding grid - second from the filament - is connected to the plus anode batteries. Handsets' are included between the anode and the lamp plus anode batteries. To use a tube amp is not enough battery glow. It is also necessary that the anode of the lamps were cast from the high voltage anode batteries.


Posted at 12:59 pm by moziie
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