Drive circuit interface between microprocessor and printer - has two groups of power transistors supplied from separate current sources to reduce number of logic elements

摘要

The circuit drives several electromechanical transducers and can be used. e.g. as an interface between a microprocessor and a mechanical, magnetically operated printer. The number of logic elements and non-intergratable components employed is reduced by applying the data signals that select the electromechanical transducers directly to the bases of their associated power transistors. The transducers are in the power transistors' collector circuits. The power transistors' collectors are connected in two groups to two separate supplies. The emitters of the two groups of transistors are connected via the collector-emitter paths of two clocked switching transistors to a control current source.