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Electric power controller






Be careful sufficiently so as not to be shocked
because this circuit handles the commercial power(AC100V or more).

I introduce the electric power controller which used the bidirectional triode thyristor(TRIAC). This circuit can control the electric power with the one variable resistor.
This circuit is used for the dimmer which changes the light of the bulb. This circuit changes the quantity of the electric current which flows through the load with the bidirectional triode thyristor and controls the electric power. It is only the alternating voltage that can be controlled with this circuit and it isn't possible to do the control of the DC voltage.
Because it controls the passing time of the alternating current by the bidirectional triode thyristor, the electric current which flows through the load is not the clean sine wave form. Because it is, there is limitation in the equipment which can be controlled with this circuit.
The bidirectional triode thyristor is generally called by the trade name TRIAC.

The equipment which can be controlled
The equipment which works by the resistance.
Such as the the tungsten-filament lamp, the soldering iron and so on.
The equipment which is using the AC series motor(with the brush).
Such as the drill, the electric fan, the cleaner and so on.

The equipment which can not do the control
The fluorescence light.
The synchronous motor(using the capacitor)
As for the synchronous motor, the number of rotations is decided by the frequency of the alternating current. So, basically, it isn't possible to control with the circuit this time. However, the torque(power to turn) of the motor declines when the electric current which flows through the synchronous motor decreases. With it, the revolution can be slowed down. In this case, with the load which is applied to the axis of the motor, the number of rotations isn't constant.

The electric power which can be controlled is decided by the permission value of the electric current which can pour into the TRIAC. I used the TRIAC which can apply the 12-A electric current to the circuit this time. In the calculation, in case of AC 100V, a maximum of 1200 W can be controlled but in the actual use, about 700 W or 800 W are safe.

When using the circuit at more than AC 100V( e.g. AC 200V), the permission voltage of the capacitor must be considered in addition to the rated voltage of the TRIAC.