JPH02268509A - Oscillator - Google Patents

Abstract

PURPOSE:To prevent oscillation from being stopped by cutting off a current on a resistor connected to the anode of a programmable unijunction transistor with an oscillation output signal. CONSTITUTION:The oscillation can be obtained by energizing the programmable unijunction transistors P1 and P2 alternately. Assuming that the energized states between the anodes A and cathodes K of the programmable unijunction transistors P1 and P2 are set accidentally, transistors Q1 and Q2 are energized, and transistors Q3 and Q4 are de-energized, and no power source Vs is applied on both resistors R1 and R2. In such a way, a state where the power source of a multivibrator is applied can be set again, which restarts an oscillation process.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is based on the product name Programmable Unijunction.
It relates to an oscillator (multivibrator) using a transistor (hereinafter referred to as PUT) or a double base diode.

(Prior Art and Problems) FIG. 2 shows the circuit configuration of a multivibrator using PUT. The multivibrators in the figure are PUT, P, and P
UT and Pl alternately discharge the current of the charging capacitor C and oscillate. That is, if capacitor C is first charged from resistor R1, PUT, P discharges the charge of capacitor C at a threshold value determined by the gate potential of PUT, Pl, and the voltage between the anode and cathode of PUT, P□ becomes It becomes conductive, and then capacitor C is charged from resistor R2,
PUT, PUT at the threshold determined by the gate potential of Pl,
Pl discharges the charge of capacitor C, PUT becomes conductive between the anode and cathode of Pl, and then resistor R□
Capacitor C is charged from PUT and P□ discharges the charge of capacitor C. This process is PUT, P', and P
The circuit shown in the figure oscillates by alternating between 1 and 1.

However, in the circuit shown in the figure, if the anode and cathode of PUT and both Pt and Pl are accidentally brought into conduction, both terminals of the capacitor C become ground potential and oscillation stops.

Therefore, in the present invention, when the anode and cathode of the PUT become conductive, the current of the charging resistor connected to the anode is forcibly cut off.

(Function) With this configuration, if the anodes and cathodes of two PUTs become conductive, the anode currents of both PUTs will be cut off, so the multivibrator power can be turned on again. The oscillation process is restarted with a state equal to the state.

(Embodiment) Fig. 1 is a circuit diagram showing an embodiment of the present invention, in which V5 is a power supply, R1, Pz are PUT, C is a capacitor, Ri and Rx are PUT, P, , anode resistors connected to the anodes of Pz, R3, R1 and R5
, R6 are resistors for determining the gate potentials of PUT, P□ and Pz, respectively, Ql and Q2 are transistors that become conductive when the cathode current of PUT, P, , Pz flows to their bases, respectively.
R7 and R8 are collector resistors of transistors Q, Q2, respectively, and Q3 and Q are transistors that are conductive when transistors Q□ and Q, respectively, are not conductive, and are nonconductive when they are conductive.

Next, the oscillation operation of the circuit shown in FIG. 1 will be explained. Since the transistors Q1 and Q4 are in a conductive state when the power supply voltage V is applied and rises, the power supply voltage V is applied to the resistors R1 and R2.
3 is applied. Now, if the anode and cathode of PUT and P□ become conductive, a base current is supplied to the transistor Q1 and the transistor Q1 becomes conductive, so that the transistor Q becomes non-conductive.

While the anodes and cathodes of PUT and P□ are conducting, a charging current flows through the capacitor C between the collector and emitter of transistor Q4 and through resistor R2, and this current flows between the anodes and cathodes of PUT and P□. The flow continues as long as there is continuity between the cathodes.

When the potential of this capacitor C (anode potential of PUT, P) exceeds the gate potential of PUT, Pz determined by resistors R6 and R6, conduction occurs between the anode and cathode of PUT, P, and the base of transistor Q The charge on the capacitor C is discharged across the emitters. This discharge current makes the transistor Qλ conductive and the transistor Q non-conductive, so that the current flowing through the resistor R2 is cut off. At the same time, this discharge current flows through the base of transistor Q.
Since a negative potential is applied between the emitters and between the anodes and cathodes of PUT and P□, the anodes and cathodes of PUT and P□ become non-conductive, and transistor Q becomes non-conductive, so transistor Q3 becomes non-conductive. It becomes conductive and the power supply potential Vs is applied to the resistor R1. By applying this voltage, the voltage between the anode and cathode of resistor R1, capacitor C, PUT, and P2, and the base and
The charging current of capacitor C flows through the emitter.

Then, the terminal voltage of capacitor C (P UT , P
PU whose anode potential) is determined by resistors R1 and R4
When the gate potential of T and P is exceeded, the discharge current of capacitor C flows between the anode and cathode of PUT and Pz and between the base and emitter of transistor Q□.

This discharge current makes transistor Q□ conductive and transistor Q non-conductive, cuts off the power supply to resistor R1, and creates a negative voltage between the anode and cathode of PUT and Pz and between the base and emitter of transistor Q2. Apply a potential to make PUT and Pz non-conductive.

The circuit of FIG. 1 oscillates because PUT, P, and Pz are alternately conductive in this way.

Here, if PUT, P, and the anode of P.

If the cathodes are erroneously made conductive, the transistors Q□ and Q become conductive, and both the transistors Q1 and Q4 become non-conductive, and the power source 5 is not applied to both the resistors R and R2. For this reason, PUT, PI and P
The anode and cathode of , cannot continue to be electrically conductive, and become non-conductive, allowing the above oscillation process to be repeated again.

(Effects of the Invention) According to the oscillator of the present invention, even if the anodes and cathodes of two PUTs constituting a multivibrator become conductive and become unable to oscillate, The flowing current is cut off, creating a state in which oscillation is possible again, and oscillation is restarted.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram for explaining the prior art. Pl, Pi...PUT (double base diode) Q
l, Q4...Transistor R1, R2...Resistor C...Capacitor Fig. 1

Claims (1)

[Claims] Two PUTs, P_1 and P, each with a gate resistor connected between the power supply and ground, and with the cathode at ground side potential.
_2, a capacitor C connected between the anodes of the two PUTs, and charging resistors R_1 and R_2 connected to the anodes of the two PUTs P_1 and P_2 to charge the capacitor C, respectively. and means for interrupting current flowing through resistors R_1 and R_2 connected to the anodes of the two PUTs using an oscillation output signal.