Design a collector-coupled monostable multivibrator using an n-p-n silicon .. An emitter-coupled monostable multivibrator in Fig.8p.2 has the following. PURPOSE: To attain stable detection against a temperature change by not using a transistor(TR) but using a comparator receiving an emitter output so as to. Collector coupled and complementary collector coupled astable multivibrators —. Emitter coupled astable multivibrator mono stable and bistable multivibrator.

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This section does not cite any sources. While not fundamental to circuit operation, diodes connected in series with the base or emitter of the transistors are required to prevent the base-emitter junction being driven into reverse breakdown when the supply voltage is in excess of the Monostagle eb breakdown voltage, typically around volts for general purpose silicon transistors.

Operational Amplifiers, 2nd Ed.

As a result, Q2 mulrivibrator switched off. Q2 is on and connects the right-hand positive plate of C2 to ground. Unsourced material may be challenged and removed. The capacitor discharges through resistor R and charges again to 0.

Q2 collector voltage is the output of the circuit in contrast to the astable circuitit has a perfect square waveform since the output is not loaded by the capacitor.

JPH05152906A – Emitter coupled monostable multivibrator – Google Patents

Thus, the circuit remains stable in a single state continuously. The two output terminals can be defined at the active devices and have complementary states. A single pair of active devices can be used to divide a reference by a large ratio, however, the stability of the technique is poor owing to the variability of emtter power supply and the circuit elements.

It is triggered by zero or negative input signal applied to Q2 base with the same success it muotivibrator be triggered by applying a positive input signal through a resistor to Q1 base. One has high voltage while the other has low voltage, except during the brief transitions from one state to the other.


The voltage at the non-inverting terminal will be greater than the voltage at the inverting terminal of the op-amp. Pulse And Digital Circuits. Simultaneously, C1 that is fully discharged and even slightly charged to 0. Because they emjtter not need to be the same, an asymmetric duty cycle is easily achieved. During State 2Q2 base-emitter junction is forward-biased and capacitor C1 is “hooked” to ground.

JPHA – Emitter coupled monostable multivibrator – Google Patents

For example, if Q2 is on and Set is grounded momentarily, this switches Q2 off, and makes Q1 monostabel. Q1 is on and connects the left-hand positive plate of C1 to ground. Similarly, Q2 remains on continuously, if it happens to get switched on first. The duration of state 1 low output will be related to the time constant R 2 C 1 as it depends on the charging of C1, and the duration of state 2 high output will be related to the time constant R 3 C 2 as it depends on the charging of C2.

In the monostable multivibrator, one resistive-capacitive network C 2 -R couupled in Figure 1 is replaced by a resistive multivibraator just a resistor. Thus C2 restores its charge and prepares for the next State C2 when it will act as a time-setting capacitor.

When triggered by an input pulse, a monostable multivibrator will switch to its unstable position for a period of time, and then emittet to its stable state.

Retrieved from ” https: By using this site, you agree to the Terms of Use and Privacy Policy. It is considered below for the transistor Q1. Switching of state can be done via Set and Reset terminals connected to the bases. In each state, one transistor is switched on and the other is switched off. If V C is the voltage across the capacitor and from the graph, the time period of the wave formed at capacitor and the output would match, then the time period could be calculated in this way:.

However, this means that at this stage they will both have high base voltages and therefore a tendency to switch on, and inevitable slight asymmetries will mean that one of the transistors is first to switch on. How long this takes is half our multivibrator switching time the other half comes from C1. An astable multivibrator consists of two amplifying stages connected in a positive feedback loop by two capacitive-resistive coupling networks.


Now the capacitor discharges towards -V sat. This is the output voltage of R 1 C 1 integrating circuit.

When the voltage of C1 right-hand plate Q2 base voltage becomes positive and reaches 0. If further trigger pulses do not affect the period, the circuit is a non-retriggerable multivibrator. For the circuit in Figure 2, in the stable couple Q1 is turned off and Q2 is turned on. As its right-hand negative plate is connected to Q2 base, a maximum negative voltage – V is applied to Q2 base that keeps Q2 firmly off. Multivibrato this reason Abraham and Bloch called it a multivibrateur.

As its left-hand negative plate is connected to Q1 base, a maximum negative voltage – V is applied to Q1 base that keeps Q1 firmly off.

During State 1Q2 base-emitter junction is reverse-biased and capacitor C1 is “unhooked” from ground. The diode D1 clamps the capacitor to 0. In the monostable configuration, only one of the transistors requires protection. Assume all the capacitors to be discharged at first.

A multivibrator is an electronic circuit used to implement a variety of simple two-state [1] [2] [3] devices such as relaxation oscillatorsmohostable and eimtter. In the end, only R3 provides the needed input base current. Since it produced a square wavein contrast to the sine wave generated by most other oscillator circuits of the time, its output contained many harmonics above the fundamental frequency, which could be used for calibrating high frequency radio circuits.

Figure 1, below right, shows bipolar junction transistors.