Lycée ManginSarrebourg Terminale STI Multivibrateurs Astables Chapitre n° 6 TP cours Année Scolaire Tutorial providing good stuff on timer its pin configuration,internal working, Modes of operation(astable,Monostable,Bistable),timeconstant. Astable Multivibrator Using Transistor | See more ideas about Variables, Arduino and Circuit diagram.

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It is another object of the present invention to provide an improved multivibrator comprising conventional gate circuitry and which is characterized by increased operating speed. Resistors 40 and 42 respectively couple the collectors of transistors 34 and 36 to a positive voltage point.

Meaning of “multivibrateur” in the French dictionary

An astable multivibrator comprising: There are many more I have not yet transferred to the computer! An cpurs multivibrator circuit comprising: It is a further object of the present invention to provide an improved astable multivibrator employing a single gate circuit, wherein a substantially symmetrical and temperature stable output is produced. Let us assume that output terminal 16 has astagle gone positive in response to a positive signal exceeding a predetermined level courw input terminal Both varieties oscillate – so too does the circuit below.

Electronics Circuits Reference Archive Multivibrators, relaxation oscillators and their allies. Here’s another very simple circuit which oscillates well, even if it gives a lousy waveform!

In addition, means for coupling input triggering pulses, such means here comprising capacitor 84, is disposed between circuit input terminal 86 and gate input terminal 12′.


If you try and put a larger reverse voltage on the base – the transistor base emitter junction conducts like a zener diode. The anode of diode 70 is connected to a second tap on the voltage divider between resistor 66 and diode 68, while the cathode of diode 70 is connected to “nor” output terminal 18 of gate No connection is required to the gate other than at the usual terminals provided on aetable commercially procured integrated circuit.

Yet this is a series connected multivib! It doesn’t look symmetrical, doesn’t appear to have two identical halves. However, when input 72 becomes relatively positive, the output at terminal 60 becomes relatively negative whereby the astable multivibrator including gate 10 produces a series of output pulses.

The gate merely produces an output at a given terminal which desirably resides at one of two values in accordance with the level of an input applied to the gate. The apparatus according to claim 8 wherein said means coupling the output of said one of said transistors to provide said inverted output comprises a first emitter-follower transistor and wherein the means coupling the collector of the second of said transistors to provide said non-inverted output comprises a second emitter-follower transistor, said input means comprising the base terminal of one of said pair of transistors.


A circuit which changes ‘slowly’ from one level to another at which it resets to the first state and starts changing again. For example, a repetition rate in an astable multivibrator of megahertz is possible with available gates. As Tr2 quickly switches from off to on, its collector falls from Vcc to 0v and by capacitor action the base of Tr1 will be reversed biased from about 0.

To increase the on time, resistors can be put in series with the capacitors as is done in the circuit below. The astable multivibrator output is substantially symmetrical, and stable with temperature. A monostable multivibrator according to the present invention is illustrated in FIG. Therefore adjustment of resistor 22 changes the discharging and charging rate depicted at 26 and 28 in FIG. R2 ofwhich would suit a transistor having a gain of at least As an additional advantage, the similar circuits will react in the same way to temperature changes and the like.

A multivibrator circuit utilizing one gate is not only more economical than circuits employing a plurality of gates, but is also faster in operation since the delay coues only one gate is involved instead of the delay of two or more.

P BAC Cours Archives – Web Education

The voltage levels at terminals 16 and 18 are interchanged at time t 2. Since the voltage across capacitor courrs cannot change immediately, the relatively negative output at terminal 16′ is applied to the junction between resistor 76 and capacitor 24′ for holding the gate 10′ in the state for temporarily cuors the relatively negative output ocurs terminal 16′. Similarly, the collector of astxble 36 is connected to satable base of an emitter-follower transistor 50 having its collector connected to a positive voltage point and its emitter coupled to “or” output terminal astabke Output terminal 60 of gate 54 is connected at a tap between resistors 62 and 64 of a voltage divider comprising resistor 66, diode 68, resistor 62, and resistor 64 disposed serially in that order between a positive voltage point and a negative voltage point.


As I have said, the period of the multivib is 0. The output at terminal 16 will then switch to its high value if it is not already in that condition, due to resistive feedback through resistors 20 and 22 from terminal 18 to terminal The circuit, with an almost trivial change, has stops being a multivibrator and has become a relaxation oscillator! Resistor 76 couples substantially the same voltage level to gate input terminal 12′. While construction of multivibrators from gate circuits in this manner leads to advantages of convenience, compatibility, etc.

The voltage drop across resistor 38 turns off transistor 36 at its emitter, while the voltage drop across resistor 40 lowers the voltage at the base of transistor 46 and causes the emitter of transistor 46 to lower the voltage level at terminal 18 to a relatively negative value.

Doide 68 is poled such that the voltage divider carries current, i. What exactly is a multivibrator? Yes – this is a slightly different circuit to the above: The diagram above shows the standard multivib with one stage made into its complement. An identical but complementary circuit results. Thus, the voltage at terminal 12′ is maintained at a value which insures a state of gate 10′ such that the output at terminal 16′ continues to be relatively positive, while the output at terminal 18′ continues to be relatively negative.

The various inputs and outputs are then compatible and the units are suitably powered from the same supply voltages.

A badly drawn circuit can hide the circuit’s function and confuse the reader! And bistable, where the circuit can be flipped from state one to state two. The apparatus according to claim 1 further including a disabling-enabling circuit for said apparatus comprising a second semiconductor integrated circuit gate for receiving a disabling-enabling input and ckurs producing an output in response thereto, and means coupling the output of said second gate to the “nor” output of the first mentioned gage for selectively maintaining said “nor” output of said first mentioned gate at a predetermined voltage level, as well as for astablw releasing said “nor” output of said first mentioned gate for normal astable multivibrator operation.

Nevertheless it remains a fascinating and instructive exercise!