DE1514421C3 - Integrated electronic circuit - Google Patents

Description

The invention relates to an integrated electronic circuit with at least one basic voltage amplifier circuit.

It is already known both all the elements of an integrated circuit on one side of a semiconductor body to be arranged and also to simulate ohmic resistances using field effect transistors.

It is also known to use discrete ohmic resistances through the resistance of the semiconductor material between individual active elements and capacitors.

With the known electronic manufactured using the aforementioned known principles But it wasn't switching yet

3 4

possible, integrated circuits of very low sistors of the basic voltage amplifier circuit-energy demand to realize how such is ordered.

wise for the transistorized electric drive. If you want a reusable, simple one

system of pocket watches and wristwatches needed to create a circuit, so that can be done using will. 5 of a low-pass filter happening at the output of the

One such application of the present inte- basic voltage amplifier circuit from a second However, the electronic circuit is not formed by a pole, which consists of two transistors Subject of the invention. and the output of the voltage amplifier basic

The use of complementary transistors, connected downstream, as well as by a Konin in particular of field effect transistors with isolated io capacitor, which would be interposed between the output of the two-pole control electrode, the construction of an electrical and ground.
If the circuit has a voltage and power level and only forms a very small energy amplifier, this can be achieved in this way. However, the production of the basic voltage amplifier circuit with its complementary transistors in a single crystal 15 output terminal with the control electrode of a first is connected with great difficulty and requires a plurality of transistors which are themselves connected in series with operations. a second transistor is connected, whose control

The invention is based on the object of this electrode with that of the transistor of the Spannver-difficulties to avoid and an integrated stronger basic circuit is connected, the first electronic circuit with at least one span 20 and the second transistor either with the basic voltage amplifier circuit indicate that there is no voltage source for the periodic supply voltage to the resistors and a very low energy requirement for supplying the basic voltage amplifier circuit has and nevertheless without particular difficulties or with a voltage source for a continuously producible is. borrowed supply voltage is connected.

According to the invention, this object is achieved in that the circuit is used to form a bistable solves that the voltage amplifier basic circuit used by multivibrators, so this can be a field effect transistor with isolated control happen that he verelectrode two each with a low-pass filter and a capacitor is formed which entin linked basic voltage amplifier circuits Series with a voltage source for one peri-holds, the output of which is one of the voltage sources Supply voltage are connected, with the 3 ° amplifier basic circuits connected filter with Connection point of the transistor and the condenser- the control electrode of a transistor parallel to the sators the output of the voltage amplifier basic transistor of the other voltage amplifier basic circuit represents. circuit is connected.

Thereby the accommodation of further components is possible. A frequency divider can be connected to the circuit

ments on the same side of the voltage amplifier if he has a first pair of voltage amplifier basic circuit supporting semiconductor body contains basic circuits, with their outputs depending on the fact that the not to the voltage one transistor as a two-terminal and parallel another amplifier basic circuit belonging components including transistor is connected and their outputs are generous Capacitors and transistors are connected to a low-pass filter with the control electrode of the Traneinem Semiconductor base material of the same conductor 40 sistor of a voltage amplifier base circuit of a type are formed. second pair of voltage amplifier basic

It is useful if all transistors lines are connected, the output of this Field effect transistors with isolated control electrode basic voltage amplifier circuit on the one hand with the are. Control electrode of the other transistor of the first

If it is such a circuit, its 45 pairs of basic voltage amplifier circuits Transistors and capacitors on one side and on the other side with the control electrode of the to the same surface of a monocrystalline semiconductor output of the same circuit connected in parallel body are formed, then it is recommended in the transistor is connected.

Interest in simplifying the production of a particularly simple construction results,

Arrangement in which the source or sink of the transistor circuits, which form the two pairs of voltage amplifier-voltage amplifier basic circuit, of the same pulse-shaped or pesistor are arranged in such a way that they are simultaneously fed a periodic voltage, the frequency of which is divided by the electrodes of the capacitor of this voltage shall be,
Form amplifier basic circuit. The circuit according to the invention has the

There can also be a simplification 55 advantage that it is particularly easy to achieve and reduce the interaction between different electronic devices, such as different elements, that the two frequency dividers, power amplifiers, bistable multi-electrodes, the basic voltage amplifier vibrators, etc. Effect transistors with an insulated electrode, arranged by way of the integration of field forming transistors in such a way, are allowed, that one surrounds at least a part of the other 60 with only transistors and capacitors. In order to be able to use the formation as components in such a circuit, which results in a considerable inversion zone under the connections, which results in energy savings.
To avoid control electrode, one can use the current- In the drawings, which show an embodiment

form a circle so that the semiconductor body point to its invention and several variants thereof, the transistors and capacitors supporting upper 65 is or are

area at least one stronger than the rest of the half-F i g. 1 has a perspective view of the Ausfühleiterkörpers doped zone, which compared to approximately example,
the connections of the control electrode of the Tran- Fig.2 a section along the line II-II of Fig. 1,

Fig. 3 is a section along the line III-III of Fig. 1,

F i g. 4 shows the circuit diagram of the device according to FIG. 1,

F i g. 5 and 6 two characteristics of the device according to FIG. 1,

F i g. 7 and 8 show two views of one in the device according to FIG. 1 field effect transistor used with isolated control electrode,

9 and 10 show two characteristics of the field effect transistor according to FIG. 7,

11 shows an illustration of another embodiment of a field effect transistor with an isolated Control electrode,

Fig. 12 is a section along the line XII-XII in Fig. 11,

FIGS. 13 and 14 show two variants of the integrated circuit of the devices according to FIG Fig. 1,

Figures 15 and 16 are graphical representations of Characteristics of the variant according to FIG. 14,

FIG. 17 shows a circuit of a variant of the integrated circuit of the device according to FIG. 1.

The integrated circuit shown in FIGS. 1, 2 and 3 consists of a semiconductor single crystal 1, for example of p-conductive silicon. The single crystal 1 is shown in FIG. 1 shown without part of its thickness: this has been omitted to facilitate illustration on a single scale. On its upper surface, the single crystal 1 has three η-conducting monocrystalline zones 2, 3 and 4, which can be obtained, for example, by a diffusion process. The structure of each of the three zones 2, 3 and 4 is provided so that they can form the sources and sinks of three field effect transistors with an isolated control electrode. In this way, zones 2 and 3 with a first control electrode 5 form a first transistor T ₁ , zones 3 and 4 with a second control electrode 6 and a third electrode 7, a second transistor T ₂ and a third transistor T _3, respectively. The electrodes 5, 6 and 7 and the zones 2, 3 and 4 are insulated by a thin layer 8, for example as silicon oxide. The device has two further electrodes 9 and 10 which connect the transistor T ₁ to a supply voltage source S ₁ . The electrode 9 is connected to the transistor T ₁ via a capacitor C ₁ which is formed by itself, by the insulating layer 8 and by the zone 3. The electrode 10 is connected to the transistor T ₁ through the zone 2, with which it forms a contact 11. The electrode 10 is connected to the transistor T _{2 via a capacitor C 2} which is formed by itself, by the insulation 8 and the zone 4. The control electrodes 6 and 7 of the transistors T ₂ and T ₃ are in contact with the zone 3 and 4, respectively, by means of the contacts 12 and 13.

The electrodes 5 and 10 are each connected to an input terminal 14 and 15, respectively, which are intended for this purpose are to be connected to a source supplying the control voltage. The electrode 10 is also connected to one of the output terminals, namely to terminal 16; the other output terminal 17 is connected to the electrode 7. The crystal 1 is through a contact, not shown, with a common point (the ground) connected. It can also be negative on this common point be polarized.

As can be seen, the integrated electronic circuit consists of a single block, in in this case the single crystal ingot 1.

Fig. 4 shows the circuit diagram of the integrated electronic circuit described above. This integrated circuit has a basic circuit which is formed by the _{transistor T 1} connected in series _{with the capacitor C 1} and the voltage source S ₁ . The voltage source supplies a periodic voltage V ₀ in the form of rectangular pulses acting in one direction. The control electrode 5 of the transistor T ₁ is connected to the terminal 14, which is intended to be connected to a source V _{e which supplies the control voltage.} The integrated circuit also has a harmonic filter which connects the basic circuit to the output terminals 16 and 17 and which is formed by the transistors T ₀ and T ₃ and the capacitor C ₂ . The transistors T ₂ and T ₃ are opposed to one another and connected in such a way that they each form a two-terminal network, that is to say that they have a characteristic similar to that of a diode.

The transistors of the circuit described are field effect transistors with an isolated control electrode. Such a transistor is shown in FIG. 7 and 8, and Figs. 9 and 10 show its operating characteristics.

As can be seen, the field effect transistor has a drain A and a source K, which are formed by two monicrystalline η-conducting semiconductor zones which have a p-conducting single crystal. The control electrode E is separated from the other two electrodes A and K by an insulating layer. separately, from where the term “insulated control electrode” comes from. In the following, B and L denote the width and the length of the channel, ie the section of the single crystal P lying between the two zones A and K.

If a direct voltage V _{0 is applied} between source K and sink A (Fig. 8) and a voltage V _{e is} applied between cathode K and control electrode E , a certain value V _en ( Fig. 10) has reached, under the insulating layer / an inversion zone, which allows a current i to flow. 9 shows the dependence of the current / on the voltage V _n for different values of the voltage V _e . As can be seen, there is a certain value of the voltage V ₀ , in particular the value

V ~~> V - V

an, a saturation of the current i for each value of the voltage V _e.

The saturation current of a given field effect transistor is determined by the following ratio:

where K is the constant which depends on the capacitance of the layer / and on the effective mobility of the charge carriers in the influenced inversion zone.

Fig. 10 shows the square root of the saturation current / _s as a function of the control voltage V _e .

When considering the in F i g. 4 it can be determined that it is a

Voltage amplifier stage and that the _{circuit formed by the transistor T 1} , the capacitor C ₁ and the voltage source S ₁ must be a basic voltage amplifier circuit. This basic circuit differs from the known ones in the lack of resistors and in the type of supply voltage. It is therefore useful to investigate the conditions under which such a circuit actually forms a voltage amplifier circuit.

_Let it be assumed that V eQ = O.

For one input voltage

V "<

K'T

15th

where T is the period of voltage V ₀ and K 'is a constant equal to the expression Ky- (see above), is the mean value of voltage V ₁

_V ₀ __ K'T

^lm

and for an input voltage

25th

2C ₁ F ₀
K'T

is this mean

^ ₁ V ₀

^{in the} 2 Κ'TV. * '

The reinforcement

is greatest for

'ITO

dVe

2C ₁ V ₀ K'T

and its worth is

dV _im Τ KT ¹ V ₁

dVe

35

40

45

C ₁

It is obvious that the return current of the pn junction at zone 3, which at the same time forms the drain of transistor T ₁ and an electrode of capacitor C ₁ (see FIGS. 1 and 4), is at most equal

60

T

have to be.

For a pn junction with a surface area of, for example, 2 · 10 ~ ^e cm ² and if a silicon crystal is used, a value of 10 ~ ¹⁰ to 10 ~ ⁿ A is easily obtained for this return current. If, on the one hand, for the other electrode of the capacitor C ₁ , which in this case is formed by part of the electrode 9 (FIGS. 1 and 3), a surface of 10 ° cm ² and, on the other hand, for the insulating layer 8, which in this case consists of silicon oxide (FIG. 1 and 3), assuming a thickness of 1000 A, a capacitance of approximately 0.035 pF _{is obtained for the capacitor C 1.} Taking into account the latter value of the reverse current and assuming that the supply voltage V ₀ = 3 V, the period T of this voltage can be at most 10 ~ ³ seconds.

For the transistor T ₁ (FIGS. 1, 7 and 8) a value of 10- «A / V ² can easily be achieved for the constant K '.

Taking into account the above values, the gain is

i ^ eioo.

It should be noted that the maximum power consumption of this amplifier is 10 ~ ¹⁰ W.

F i g. 6 shows a variation of the form of the output voltage V ₁ as a function of the input voltage V _e , the variation of which in FIG. 5 is shown. As can be seen, for V _e = 0, V _{1 is} a square-wave voltage equal to V ₀ . As V _e increases, the shape of V _{1 changes} more and more to a triangle, the base of which becomes smaller as V _{e increases.}

It can be seen from this that the _{circuit formed by the transistor T 1} , the capacitor C ₁ and the voltage source S _{1 is} actually a voltage amplifier circuit. It can also be seen that the implementation of such a circuit in the form of an integrated circuit is relatively simple, which is by no means the case with a circuit with resistors which is to experience an amplification in the same size range with the same consumption.

It should be noted that the supply voltage, which in the present case is a voltage in the form of a A series of unidirectional impulses is also a voltage in the form of one in both directions acting pulse train as well as a sinusoidal alternating voltage.

From the above it can be seen that the problem of integration through the design a basic voltage amplifier circuit which has only one transistor and one capacitor and thus has neither resistors nor complementary transistors, is largely simplified. the Such an amplifier circuit is implemented by using a periodic supply voltage enables.

To produce the electronic circuit described above, for example known methods of photolithography can be used. This procedure is based on that certain substances can be made insoluble by ultraviolet pre-exposure. To the To diffuse zones 2, 3 and 4 into the single crystal 1, its surface is first oxidized, then covered with a photosensitive layer and then through a photographic negative showing the Covered areas where zones 2, 3 and 4 are to be produced, exposed to ultraviolet light. The oxide layer covering these areas is then dissolved in order to carry out the diffusion.

When this is finished, the entire surface of the single crystal is oxidized again, whereupon the Oxide layer, as mentioned above, is removed from the places where the contacts 11, 12 and 13 should appear. In order to manufacture these different electrodes, it is applied to the entire surface applied a metal layer, for example a

609 626/350

9 10

Aluminum layer, which is then also placed on photo-ground. The supply voltage V ₀ is lithographically removed from the points at which the source S ₁ and the control voltage V _e of one of them must not be present. The second source S _{2 is} supplied via the fact that one of the electrodes of the capacitors C ₃ and C ₃ .

sators formed by the sink of the field effect transistor 5 The frequency divider circuit described works

, it allows you to only have a single metal- as follows: The circuit must be designed in such a way that

lische layer has to apply what the production _{that the ratio} Γ _{of the transistor T}

very simplified. C.

It is to be noted that it is very important in integrated electricity and the capacitor C ₃ and from the Transikreisen often, the interaction io sturgeon T ₆ and the capacitor C ₃ 'existing between the different elements, as far as complex circuit is greater than the same Able to reduce. Thus, for example, the ratio of T ₁ and C ₁ or of T ₁ ' and C _{1 can} prove the coupling between the two of a standing circuit complex.
AC voltage exposed zones of a field The mode of operation is described from the point in time from effect transistor with insulated electrode and other 15 going, where the capacitor C ₂ charged zones of the integrated circuit is greatly reduced and the capacitor C ₂ 'is discharged. The transistor, in that one of the zones with the other T ₆ ' is conductive, and the transistor T ₆ is blocked, the same transistor is surrounded, as from It must be mentioned that those from the sources Fig. 11 and 12 can be seen is. On the other hand, the voltages V _e and V _{0 supplied around S 1} and S ₂ are equal in the case before the eventual formation of an inversion zone is below 20.

To avoid the terminals of a control electrode, a pulse of voltage V _e and as a result

Among these connections, a heavily doped voltage V _{0 can also} cause a very short one

Zone, such as zone K in Fig. 11, voltage pulse at point Γ, which the transistor T ₁ ,

diffused into the crystal, which makes it conductive for such a short time that the condensation

Line type like this is. 25 Sator C ₁ receives practically no charge, so that the

The integrated circuit of the execution case voltage V ₀ at point ΙΓ appears. Simultaneously

Spiels is a simple electronic circuit, the voltage V _{e appears} at point I because of the

which from a voltage amplifier _{basic circuit transistor T 6 is} still., is blocked, so that the tran-

and consists of a filter, but it is understood that the transistor T _{1 is made} conductive and the capacitor C ₁

of itself that the integration possibility of these 3 "is charged. The voltage at point II becomes

Basic circuit also includes the integration of any thus zero. On the other hand, the transit

T ₇ interferes with other, more complicated electronic circuits due to the voltage appearing at point I.

lets which, as a basic circuit, also make this elementary circle conductive, which is the relative

used. The described voltage amplifier- slow discharge of the capacitor C ₂ via the

The basic circuit can be used to form various electrical 35 transistor T ₂ . In the meantime, the

tronic circuits are used. Capacitor C ₂ 'via the transistors T ₅ ' and T ₃ '

F i g. 13 shows the circuit diagram of a bistable relatively "slow by the voltage on."

Multivibrators charged with two voltage amplifier base point ΙΓ.

Circuits T ₁ , C ₁ or T ₁ , C ₁ , which are based on the voltage due to the effect of a diode comparable

voltage source S _{1 are} fed. Each of the two 4 ° Baren transistor T ₅ 'remains the capacitor C ₂ '

On the one hand, Kreise is charged with its output to an output until the positive edge of the next

input terminal 16 'or 16 and on the other hand via two pulses of the voltage V _e the circuit back in

transitions connected to each other as a two-pole offset their initial state,

disturb T ₂ , T ₃ or T ₂ ', T ₃ ' to the control electrode. FIGS. 16a to 16h show the voltage

of a transistor T ₄ or T ₄ 'connected to 45 different points of the above-described current

the transistor T ₁ or T _{1 of} the other voltage circuit as a function of the control voltage V _e

basic amplifier circuit is connected in parallel. 15. From this it can be seen that the fre-

_{two transistors T 2} connected against one another, sequence of the output voltage (Fig. 16e to 16h)

T ₃ or T ₂ ', T ₃ ' form with the input capacitance which is twice smaller than the input frequency

Transistor T ₄ 'resp. T ₄ a filter. 50 (Figure 15). So it really is one

Depending on whether the control voltage V _e or V / frequency divider stage.

is applied, the circuit takes either the In the embodiment of the described fre-

one or the other of their two stable states. frequency divider are the control voltage and

The bistable multivibrator described can take the supply voltage, both of which are equal, from two

can be easily integrated because it has only transistors 55 independent voltage sources S ₁ and

of the same type as well as capacitors. S ₂ delivered. Of course, it can also only

F i g. Figure 14 shows the circuit diagram of a stage in which a single voltage source can be used. It

Frequency divider circuit with two voltage amplifiers is obvious that such a circuit also

Core basic circuits T ₁ , C ₁ and T ₁ ', C ₁ . Point II can work just as well if the

the circuit T ₁ , C ₁ is on the one hand over one than 60 two voltages to sinusoidal voltages

Two-pole switched transistor T, and one of or around voltages in the form of differently shaped

T ₂ , T ₃ and C ₂ formed filter to the control electrode pulses. Because of the presence of the

of a transistor T ₆ 'and on the other hand via a transistor T ₅ and T ₅ ', the frequency of the

Transistor T _{7 connected} to ground. In the same way, control voltage V _{e is} different but lower

the point ΙΓ of the circuit T ₁ ', C ₁ ' on the one hand above 65 as the frequency of the supply voltage V ₀ . In this

a transistor T ₅ 'and one of T ₁ ', T ₃ 'and C ₂ ' is of course a part

formed filter to the control electrode of a transmission of the voltage V _e .

stors T ₆ and on the other hand via a transistor T ₇ 'Fig. 17 shows a variant of the above-described

basic voltage amplifier circuit. As can be seen from this, the output is connected to the control electrode of a second transistor T _s , which is connected in series with a third transistor T ₉ , the control electrode of which is connected to the input of the circuit.

A DC voltage source S _s feeds the transistors T ″ and T _n .

Thus, in reality there are two amplifier circuits controlled by the same input voltage. The first of these circuits consists of the transistor T ₁ , the capacitor C ₁ and the source S ₁ , while the second circuit consists of two transistors T ₈ and T ₉ and the source S ₃ , the first transistor T _{8 of} the second circuit representing the charge is controlled by the output circuit of the first circuit.

It is easy to see that in the absence of the input voltage V _e, the transistors T ₁ and T ₉

are blocked, while the transistor T _{8 is} conductive, so that the output voltage receives V _s. If a sufficient voltage V _e is present, the voltage V _{s is} zero because the transistor T _{8 is} blocked and the transistors T ₁ and T _{9 are} conductive.

It follows that the amplifier circuit in this variant not only the voltage, but also strengthened the line.

It must also be noted that the DC voltage source S _{3 can} also be replaced by a source that supplies a periodic voltage, such as. B. the source S ₁ .

It goes without saying that the basic voltage amplifier circuit of the variant described above to form the same electronic circuits as the basic circuit according to FIG. 4 used can be, d. H. of circuits that only have transistors of the same type, as well as capacitors exhibit.

In addition 5 sheets of drawings

Claims (11)

Patent claims: 1. Integrated electronic circuit with at least one basic voltage amplifier circuit, characterized in that this basic voltage amplifier circuit is formed by a field effect transistor (T ₁ ) with an isolated control electrode and a capacitor (C ₁ ), which is in series with a voltage source (S ₁ ) for a periodic supply voltage are connected, the connection point of the transistor (T ₁ ) and the capacitor (C ₁ ) representing the output of the basic voltage amplifier circuit. 2. Circuit according to claim 1, characterized in that the not to the voltage amplifier basic circuit Components belonging to it are all capacitors and transistors, which are based on a semiconductor base material of the same Line type are formed. 3. Circuit according to claim 2, characterized in that all transistors are field effect transistors with an insulated control electrode. 4. Circuit according to one of claims 1 to 3, its transistors and capacitors are formed on one and the same surface of a monocrystalline semiconductor body, characterized in that the source or the sink of the basic voltage amplifier circuit forming transistor are arranged so that they are simultaneously one of the two electrodes of the Form capacitor of this basic voltage amplifier circuit. 5. Circuit according to one of claims 1 to 3, its transistors and capacitors are formed on one and the same surface of a monocrystalline semiconductor body, characterized in that the two electrodes of the basic voltage amplifier circuit forming transistor are arranged in such a way that the one at least a part that surrounds the other. 6. Circuit according to one of claims 1 to 3, its transistors and capacitors are formed on one and the same surface of a monocrystalline semiconductor body, characterized in that the semiconductor body has the transistors and capacitors on it supporting surface has at least one more heavily doped zone than the rest of the semiconductor body, the opposite of the connections of the control electrode of the transistor of the basic voltage amplifier circuit is arranged. 7. Circuit according to claims 1 to 3, characterized by a low-pass filter which is formed at the output of the basic voltage amplifier circuit by a two-pole, which consists of two transistors (T ₂ , T ₃ ) and is connected downstream of the output of the basic voltage amplifier circuit, and by a capacitor (C ₂ ), which is connected between the output of the two-terminal network and ground. 8. Circuit according to one of claims 1, 2, 3 or 7, which forms a voltage and power amplifier, characterized in that the basic voltage amplifier circuit (T ₁ , C ₁ ) is connected with its output terminal to the control electrode of a first transistor (T ₈ ) which itself is in series with a second transistor ( T ₉ ) is connected, the control electrode of which is connected to that of the transistor (T ₁ ) of the basic voltage amplifier circuit (T ₁ , C ₁ ), the first and the second transistor either with the voltage source (S ₁ ) for the periodic supply voltage for feeding the Basic voltage amplifier circuit (T ₁ ^ ₁ ) or connected to a voltage source for a continuous supply voltage. 9. Circuit according to one of claims 1, 2, 3 or 7, which represents a bistable multivibrator, characterized in that it contains two basic voltage amplifier circuits (T ₂ , T ₃ ; T ₂ ', T ₃ ') each connected to a low-pass filter, wherein the output of the filter connected to one of the basic voltage amplifier circuits is connected to the control electrode of a transistor (T ₄ ; T ₄ ') in parallel with the transistor of the other basic voltage amplifier circuit. 10. Circuit according to one of claims 1, 2, 3 or 7, which forms a frequency divider, characterized in that it contains a first pair of voltage amplifier basic circuits (T ₁ , C ₁ ; T ₁ , C ₁ '), with their outputs each one Transistor as a two-pole (T ₅ , T ₅ ') and in parallel another transistor (T., T ₁ ') is connected and its outputs via a low-pass filter (T ₂ , T ₃ ; T ₂ ', T.,') with the Control electrode of the transistor (T ₀ ', T ₆ ) of a voltage amplifier basic circuit of a second pair of voltage _{amplifier basic circuits (T 6} ', C ₃ '; T ₆ , C ₃ ) are connected, the output of this voltage amplifier basic circuit on the one hand with the control electrode of the other transistor of the first Pair of voltage _{amplifier basic circuits (T 1} , C ₁ ; T ₁ ', C ₁ ') and on the other hand is connected to the control electrode of the transistor connected in parallel to the output of the same circuit. 11. Circuit according to claim 10, characterized in that the two pairs of voltage _{amplifier basic circuits (T 1} , C ₁ ; T ₁ ', C ₁ '; T _f ', C ₃ ; T ", C ₃ ) of the same pulse shape! or periodic voltage (V _e ; 5th,), the frequency of which is to be divided.