Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Current Source Control for Electroerosion Printing

IP.com Disclosure Number: IPCOM000081600D
Original Publication Date: 1974-Jul-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Galetto, LV: AUTHOR [+2]

Abstract

Current sources 1,2, -n are used to deliver energy to the electroerosion stylii in a printer, as shown in Fig. 1.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 75% of the total text.

Page 1 of 2

Current Source Control for Electroerosion Printing

Current sources 1,2, -n are used to deliver energy to the electroerosion stylii in a printer, as shown in Fig. 1.

As shown in Fig. 2, the input 10 of each source is allowed to go positive by a digital switch, not shown. Current supplied through resistor 11 turns on transistors 12 and 13, which are connected in a Darlington configuration for additional current gain. Resistor 14 serves to assure that transistor 13 will be turned OFF quickly when transistor 12 turns OFF. Current through transistors 12 and 13 passes via terminal 15 to stylus 9, paper 5 and contact 7 where it returns to the positive terminal of supply VE6.

The current is supplied from the negative terminal of VE6 and through resistor 16 to the transistors 12 and 13. When the voltage across resistor 16 equals the sum of control voltage Vc4 and the base-emitter operating voltage of transistor 17, transistor 17 conducts and absorbs the excess current from resistor 11, so that the output current becomes fixed at the level which causes this action.

Resistor 18 has a low value and serves only to dampen very high frequency oscillations. Capacitor 19 may or may not be present; if used it reduces the rate- of-rise of the current, in accordance with the time constant associated with it and resistor 11. The circuit turns OFF when the digital control restores input 10 to zero volts.

The values of resistor 16, base-emitter voltage of transistor 17 and the voltage...