800 Watt musik/lys modulator

Varenr: SK1006

How it Works:
Let us first discuss this new component that is used in the modulator, the OPTOCOUPLER or OPTOISOLATOR. This is a device that includes in the same casing a LED and a PHOTOTRANSISTOR or a light sensitive SCR or a TRIAC. The LED is used as the input and the signal is transmitted optically to the output device which converts it back to electrical signal. Thanks to this arrangement it is possible to achieve total isolation between input and output and the device is used extensively in cases where the two stages to be linked have a great voltage difference. As you can see from the circuit diagram of the modulator the signal is applied across the LED of the optocoupler at points 1 and 2 on the p.c. board through a resistor R1 and a potentiometer P1. The potentiometer adjusts the input sensitivity of the circuit and the resistor is used to protect the from very high input signals when the potentiometer is set for the maximum sensitivity. When an audio signal is applied at the input of the circuit the LED will flicker following its changes in amplitude. The LED is emitting in the infrared part of the spectrum and is used to drive a TRIAC inside the package that is sensitive to the same type of radiation. This TRIAC is in turn used as a TRIAC driver in order to control another TRIAC capable of handling larger cur rents. The resistor R2 that you can see connected in series with the driver and the TRIAC gate is used to protect the optoisolator and the gate from excess current at the signal peaks. If you connect a lamp in series with the TRIAC at points 3 and 4 and the mains supply at points 5 and 6 of the board this lamp will follow the variations of the input signal and the result will be a simple but effective light modulator. The isolation between the two parts of the OPTOCOUPLER is greater than 1500 V and this makes it totally safe for any installation.