| ??? 09/13/10 11:16 Modified: 09/13/10 12:49 Read: times |
#178544 - Still no specific reason for a matrix! [Ed] Responding to: ???'s previous message |
Ninad Sonawane said:
The reason why i mentioned relays is that i thought it would require less space than transistors with their biasing for so many pins. So what size relays were you thinking of?? And what size transistors? Had you not considered ICs? The purpose of the printer is to print or punch cards Print? or Punch? or is it a dual-function machine to do both printing & punching? That's why the matrix. No reason why that should require a matrix - is there? As far as I recall, the old 80-column card punches would punch 1 column at a time, and advance the card for the next column... Edit: For example: Wikipedia said:
The heart of the [IBM] 024 and 026 keypunches was a set of twelve precision punches, one per card row, each with an actuator of relatively high power. Punch cards were stepped across the punch one column at a time, and the appropriate punches were activated to create the holes, resulting in a distinctive "chunk, chunk" sound as columns were punched.
http://en.wikipedia.org/wiki/Keyp...024.2C_026 Here's a picture of a manual punch - it clearly shows the principle (click for full-size): 
You can find all this and more by Googling "card punch mechanism"... |
| Topic | Author | Date |
| I/O pin extension | 01/01/70 00:00 | |
| Start by specify your need | 01/01/70 00:00 | |
| you really have to list down the full requirements | 01/01/70 00:00 | |
| A suggestion | 01/01/70 00:00 | |
| Specefic Requirements | 01/01/70 00:00 | |
| Why relays? | 01/01/70 00:00 | |
| But dot matrix printers normally don't have X*Y array head | 01/01/70 00:00 | |
| Only need *one* column of dots! [ED] | 01/01/70 00:00 | |
| Head has constant speed w/o steps even with stepper motors | 01/01/70 00:00 | |
| reply | 01/01/70 00:00 | |
| not helpful! | 01/01/70 00:00 | |
| Necessity of relays | 01/01/70 00:00 | |
| Relays are not necessary | 01/01/70 00:00 | |
| What's a "design"? | 01/01/70 00:00 | |
| Discrete or integrated | 01/01/70 00:00 | |
| So what's the reason for a slow ctar-at-a-time head? | 01/01/70 00:00 | |
| Printer Purpose | 01/01/70 00:00 | |
| Still no specific reason for a matrix! [Ed] | 01/01/70 00:00 | |
| More care while finding solution | 01/01/70 00:00 | |
| RE: "many others" | 01/01/70 00:00 | |
| Smaller than a relay | 01/01/70 00:00 | |
Relays Take Drivers Too | 01/01/70 00:00 |