#### the_merovingian

##### Member level 1

**optotriac**

I'm trying to design a circuit to control a lamp using a triac and MCU.

Ignoring the zero-cross / timing issues at the moment, I have a couple basic queries about the use of an opto-triac (MOC3020).

Taking the circuit in Figure 5 of the datasheet PDF (https://www.ohm.wz.cz/PDF/moc3020.pdf) as an example.

1. Which lamps are classed a 'resistive' and which are classed as 'inductive'? I'm assuming a standard incandescent lamp is a 'resistive' load.

2. For the resistor that sits on pin 6 - what wattage does this need to be to safely control an 80W lamp from a 220Vac UK (50Hz) supply? (If there is any maths involved I'd appreciate the equations to understand for the future)

3. Would a BTA26-600B be suitable triac (https://www.datasheetcatalog.org/datasheet/stmicroelectronics/7470.pdf)?

Thanks in advance.