1. Introduction.
With Meumann's time sense apparatus, we are unable to carry psychological experiments on acoustic sense, because as we know, it makes noises, it is troublesome for us to operate, and also takes long time to finish one experimental series. In addition to these defects, it is, therefore, hardly possible to give very short stimulus-time exposures successively in a short time. we have then made an apparatus which is quite free from any noises, and can easily give any short stimulus-time and time-intervals from 10sec. to 1/1.000sec. by mere rotations of its dial.
2. Principles of Apparatus.
The circuit diagram of this apparatus is shown in Fig 9. In Fig 9., we find the high voltage source (I), R-C circuits (II), constant voltage discharging tubes D, D
1, thyratron tubes, and relay circuits (III).
The principle of this apparatus is as the following: Using the resistance connected in parallel with the constant voltage discharging tubes and the series circuit of the condenser, the saw-toothed oscillation with any period is to be generated. The period is proportional to the relaxation time T=RC. (R is value of resistor ‘Ohm’ and C is value of capacitor ‘Farad’). And the thyratron tube is discharged by pulse current induced by oscillation, and so the discharging current of thyratron tube moves the electro-magnetic relays.
In Fig 1., R shows the resistor, C the capacitor, D the constant voltage discharging tube, the discharging voltage of which is V, and G the high voltage source.
When we assume that E (the terminal voltage of high voltage source) is larger than V, we can find the following circuit equation:
dq/
dtR+
q/C=E………(1)
where q is the positive charge in the condenser.
We can obtain the solution by resolving this diffrential equation, then
q=Q(1-ε-t/RC)………(2)
Where Q is the maximum charge charged by supplying voltage E, and ε shows the exponential function.
From the equation (2), the terminal voltage of condenser at any time is:
v=E(1-ε-t/RC)………(3)
So we can define the period of the saw-toothed oscillation as follows:
T=-t/RC=log(1-V/E)
At the movement when the terminal volltage of condenser climbes to be discharging voltage, discharging tube D discharges, and the charge of the condenser discharges for a moment through the D and
r0. Thus the grid of thyratron changes from negative potential to positive ptential.
At the same time when the thyratron tube discharges, a large current flows through the electro-magnetic relay. (See Fig 3). And we can find that
r0' has shunt C′ by switching of the electro-magnetic relay in Fig (9), and
r0 has been opened while the relay is not working.
The condenser C′ is, therefore, not charged at first. At the moment when the thyratron A is discharged, and relay begins working,
r'
0 opens and γ
0 shunts the condenser C inversely, till C′ is begins charging.
After a while, the terminal voltage of C′ reaches the discharging voltage, and D′ and B will be discharged.
Before explaining the next work of the apparatus, I should explain the following facts, shown in Fig (4), that the condenser C
o connected detween the plates of thyratron is being changed, while thyratron A is discharging.
At the moment when the positive potential becomes negative potential, it becomes constant voltage, and so the thyratron A stops its discharge, because the grid voltage is negative. Then the electro magnetic relay stops it's work, while γ
o opens and γ'
o shunts the condenser C′. The condenser C begins charging and C' stops.
After the time-interval determined by relaxation time T, the thyratron
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