Power-Supplies and Printers:

Carefully choose the "most correct" answer, if there appears to be more than one !

* Linear power-supplies

  1. Are easier to troubleshoot than swiching-power-supplies
  2. Are less expensive than switching-power-supplies
  3. Cannot supply as much power as switching-power-supplies
  4. Require about the same space requirements as switching-power-supplies

* References to a "Crowbar Circuit" in a power-supply

  1. Is a misnomer, there is no such thing
  2. Is a dangerous circuit to employ in a power-supply of any kind
  3. Is simply an "Over-voltage Protection Circuit"
  4. Is actually in reference to voltage compensation for the output

* In switching-power-supplies,

  1. The input circuit of the unit is in reality a power-supply in itself
  2. There is a switching oscillator in the output side
  3. Output ripple is easier to filter, due to it being much higher frequency than line frequency
  4. Choices 1,2, & 3 are all correct
  5. Only choices 1 & 3 are correct

* Dot-Matrix Printers

  1. May be impact or non-impact printers
  2. Are always parallel interface, rather than serial interface
  3. Are not considered in the same category as the Ink-Jet printers
  4. Are not considered as possible "Near-Letter-Quality" (NLQ) printers

* In repairing a Dot-Matrix Printer circuit board, the occurrence of a block of 4 sizable transistors

  1. Is part of the power supply circuit
  2. Is probably for the LED's, or Instrument Control Panel
  3. Is probably one of the 4-phase stepper-motor driver circuits

* The presence of a cluster of 9 (or even 24) transistors,

  1. Is obviously the print-head drivers
  2. Is simply the control circuits for the carriage motor & paper-feed motor
  3. Is part of the parallel interface drivers
  4. Is for one of the motor mechanisms, with voltage & current control

* Laser Printers

  1. Generate static electricity
  2. Use photoconductive processes
  3. Incorporate a heater, called a fuser
  4. All of the above are correct

* In a switching power supply, the largest transistor, near the "line-side" of the unit, most likely is the _______________.

* In that same switching power supply, the principle voltage regulation is with feedback from the ___________ circuit.

* The circuit that will "short-out" the output of a switching power supply, if the voltage starts to exceed the allowed
   voltage , is called the ______________ circuit.

* On observing the circuit board of a printer, the occurence of 4 transistors in a group will usually indicate     __________________________________________.

* If there are 2 sets of these 4 transistors (or a transistor array in a package), and one set of these 4 transistors is
   obviously for heavier current, they would be for the __________ ________________.

* The presence of a cluster of 9 transistors (or even 24) in a group, are obviously for the________________________.


Power_Supplies.html - SfE-DCS, ddf - 07/20/2001       PSandPtrs.sam - ami-pro - ddf - 07/11/96