Specifications

CA10 Course Notes
Sharp Electronics (UK) Limited
CE Technical Support GroupPage 12
Primary Processor
As described previously, to control the operation of the set in the standby mode a primary processor is
utilised. The circuit diagram of this part of the circuit is shown below.
Figure 10 : Primary Side Microprocessor
The two transistors Q708 and Q709 comprise a monostable, which is triggered from the mains input at
double frequency, i.e. 100Hz. The square wave signal on pin 8 ( PB6 ) is used to control the on timer.
This is necessary due to the fact that in standby, the main system microprocessor, IC101, is dormant,
i.e. no supply and therefore can not perform any functions. The off timer function is controlled within
IC101.