DE1056180B - Circuit arrangement for controlling tiltable bistable multivibrators using contacts - Google Patents

Description

The invention relates to a circuit arrangement for controlling tiltable bistable multivibrators, whose each from z. B. each two transistors or electron tubes is built and which by mechanically, magnetically or electromagnetically actuated contacts can be controlled. Such contacts experience has shown that they tend to bounce, d. that is, both when closing and opening such Contacts, the springs to which the contact pieces are attached start to vibrate and arise as a result, in a known manner, interruptions in the contact closure or, in the event of an interruption, new short-duration ones Closures that can lead to incorrect actuation in circuits that respond very quickly.

It is the purpose of the present invention to remedy this drawback by means of a circuit arrangement to remedy, in which no incorrect actuations in such devices occur in which responsive tiltable bistable to very short pulses Multivibrators can be controlled by bouncing contacts. This is achieved in that by the bouncing contact controlled multivibrator stage on from capacitance and ohmic resistances in series connection existing delay element is arranged parallel to the controlling pulse contact, whose time constant is greater than the bounce time, but less than the switching sequence time of the controlling contact. In a further embodiment of the invention, a capacitor is used in parallel with the controlling pulse contact arranged, the capacitance value is such that together with the capacitor of the the aforementioned delay element and its series resistances have a time constant of the duration of the temporal pulse interval can be achieved without the permissible control pulse duration for the following Count level is exceeded. According to a further feature of the invention, it is also possible in series to arrange an ohmic resistor to the capacitor arranged for the controlling pulse contact, at the same time the permissible control pulse duration is not exceeded and the time constants are limited can be maintained between the duration of the contact bounce time and the duration of the pulse interval. At the same time it becomes achieved that the contact in a manner known per se from the consequences of the capacitor discharge current surges is protected.

The drawing shows an embodiment with omission of all details not belonging to the subject matter. Only the first bistable multivibrator stage controlled by a non-bounce-free switching contact i is shown, and the pulse control line to any subsequent further stages is indicated by dashed lines.

Circuit arrangement for control

of tiltable bistable
Multivibrators through contacts

Applicant:

Standard electrical system Lorenz

Corporation,

Stuttgart-Zuffenhausen,

Hellmuth-Hirth-Str. 42

Wolfgang Weisser, Stuttgart,

and Wolfgang Blume, Gerlingen (district of Leonberg),

have been named as inventors

It is assumed that the transistor Tr 1 is in the conductive state in the multivibrator stage consisting of the two transistors Tr 1 and Tr 2 , whereas the transistor Tr 2 is blocked. If the controlling pulse contact i now closes, then it transfers plus potential to the one in retirement

(-), Rl, Cl, R2, (+)

charged capacitor C1, and this discharges via the two diodes DiI and Di2 and the resistors R 5, R 6 as well as the currently conductive transistor TrI and parallel to it also via R2, the transistor Tr 1 in a known manner by potential displacement the diode DiI is blocked. After the end of the pulse, the transistor Tr 2 is put into the conductive state in a known manner. The stage is thus tipped, regardless of the duration of the closing time of the contact i. After opening the contact i , the capacitor C1 charges up again. The control pulse length is determined by the time constants of the switching elements lying in the above-mentioned discharge current surge of the capacitor C1; the time constant of the timing element formed by the resistors Rl and R2 and the capacitor Cl determines the state of charge of the capacitor C 1 at the arrival of the next contact closure of i after the pulse interval. In order to achieve this state independently of the dimensioning of the elements Ci and R 2 predetermined by the maximum permissible pulse duration only after the bounce time of the contact i has expired and after it has opened, the capacitor C 2 can with such a high

909 508/286

Capacitance value must be provided that the charge only reaches a permissible value after opening the contact i , without the steeper pulse duration becoming inadmissibly high, since the capacitor C2 discharges via this when the contact i closes and does not interfere with the discharge of the capacitor Cl.

Any resistor R 3 in series with the capacitor C2 determines its state of discharge when the contact i opens and protects it from excessive current loads.

Claims (3)

Patent claims: 1. Circuit arrangement for the control of tiltable bistable multivibrators, which consist of z. B. two transistors or electron tubes are constructed by mechanically, magnetically or electromagnetically actuated contacts, which can lead to undesired incorrect operation due to bouncing, characterized in that a delay element consisting of capacitive (Cl) and ohmic switching elements in order to prevent undesired switching operations due to contact bouncing (Rl, R2) is arranged parallel to the controlling pulse contact (i) , the time constant of which is greater than the bounce time, but less than the switching sequence time of the controlling contact. 2. Circuit arrangement according to claim 1, characterized in that a capacitor (C2) is arranged in parallel with the controlling pulse contact (i), the capacitance value of which is dimensioned so that together with the capacitor (Cl) in series with the said resistors (Rl , R2) a time constant equal to the duration of the pulse interval can be achieved without exceeding the permissible control pulse duration for the subsequent counting stage. 3. Circuit arrangement according to claim 2, characterized in that in series with the controlling pulse contact (i) arranged capacitor (C2) an ohmic resistor (R3) is arranged so that at the same time the permissible control pulse duration is not exceeded and the limitation of the time constant between the duration the contact bounce time and the pulse interval duration can be maintained. 1 sheet of drawings