LS7237

LS7237 is a monolithic, MOS integrated circuit designed to control the brightness of an incandescent lamp. The output of the LS7237 triggers a triac connected in series with a lamp(See Figure 5). The lamp brightness is determined by controlling the output conduction angle (triac triggering angle) in relation to the AC line frequency (See Figure 2).

The output conduction angle of LS7237 can be varied by applying a low level pulse at the SENS input or a high level pulse at the EXT input. When implemented as shown in Figure 5, this is accomplished by touching the Touch Plate which causes the lamp brightness to change in specified steps as follows