1541 CIRCUIT THEORY

[Write amplifier schematic]

Write Amplifier Circuits

During a write operation, B must be "high". This forward biases Q7 and CR14. If _B goes "low", Q3 and Q6 become forward biased. If Q goes "low", Q5 and CR15 become forward biased, passing current flow through R/W 1. If _Q goes "low", Q4 and CR18 become forward biased, passing current flow through R/W 2.

When a write operation occurs, the ERASE coil is energized by forward biasing Q6. This demagnetizes the outer edges of the track, preventing data on one track from bleeding into the next track.