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Electronics
Electronics Catlog
DIC Catlog

Number System
Conversions Between Number System
Arithematic Operations
1's & 2's Complement
Gray Codes
Arithmetic Circuits
Logical Gates and Truth Table Funtions
Boolean Expressions
Boolean Algebra
Karnaugh Map
Multiplexer
DeMultiplexer
Encoder & Decoder
TTL Circuits
Multivibrators
555 Timer
Flip Flops
RS Flip - Flop
JK Flip - Flop
D Flip - Flop
Shift Register
Schmitt Trigger
Asynchronous Counters
Synchronous Counters
Digital - Analog Conversion
Data Flow
ROM
Memory Drives
Electronics Equation
Resistor Color Codes

Multivibrators


    Two-state devices called multivibrators are used extensively in digital electronics. The bistable multivibrators are called flip-flops and are the basic memory devices used in sequential logic. Other two-state devices include the astable multivibrator which serves as an oscillator and the monostable multivibrator ("one-shot" multivibrator) which can serve as a pulse source.


Astable Multivibrator

Astable Multivibrator

    The configuration of NAND gate inverters shown is one of many ways to create an astable multivibrator : a two-state device which is not stable in either state. If we start with point A high, then that high voltage charges the capacitor and after a time characteristic of the time constant RC will reach the threshold for switching A low and B high. Then the charging process will reverse until the transition back to the original state occurs. This circuit can be constructed from half of an IC7400 quad NAND gate.

Monostable Multivibrator


Monostable Multivibrator

    In response to a positive trigger pulse the monostable multivibrator or "one-shot" will produce a single output pulse of length t determined by the value of the resistor and capacitor. The non-retriggerable one-shot will not respond to further trigger pulses which happen during its pulse length.


Multivibrator Pluses