Quantcast 1-18.  Threshold-Detector  Circuit

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
TM   55-4920-429-13 1-18.  Threshold-Detector  Circuit. (See  FO-2,  FO-3,  and  FO-8.)  The  threshold-detector  circuits  contain  two  threshold-detector  amplifiers and  two  lamp-driver  stages.  These  control  the  on/off  condition  of  the  STATUS  A  and  STATUS  B  indi- cators. a. The  STATUS  A  threshold  detector  amplifier  U4-9  is  biased  to  +4.6  volt  dc  at  its  inverting  input by  voltage  divider  R81/R82.  When  the  input  signal  is  below  4.6-volt  dc,  the  output  at  U4-8  is-12-volt dc.  When  the  input  signal  is  above  4.6-volt  dc,  the  output  is  +12-volt  dc.  When  the  output  is  negative, transistor  Q6  is  cut  off,  and  relay  K1  is  deenergized.  The  ground  return  of  STATUS  A  indicator  thru normally-open  contacts  3,  4  is  open,  and  the  indicator  is  out.  When  the  output  is  positive,  transistor  Q6 is  turned  on,  and  relay  K1  is  energized  to  light  the  indicator.  Diode  CR11  protects  transistor  Q6  from the  voltage  self-induced  when  relay  K1  is  released. b. The  STATUS  B  threshold  circuit  operates  the  same  as  the  STATUS  A  circuit,  except  that  a  +0.76 volt  dc  bias  voltage  is  applied  to  the  non-inverting  input  of  the  amplifier  at  U4-12.  Its  output  voltage  at U4-14  switches  positive  when  input  voltage  drops  below  +0.76  volt  dc. c.  The  ground  return  path  to  the  indicators  thru  relays  K1  and  K2  is  open  with  the  SEL  1/OFF/SEL 2  switch  at  OFF.  This  prevents  spurious  lighting  of  the  indicators  when  the  discrete  signal  monitor  is not  in  use.  Buffer  diodes  CR13  and  CR14  provide  an  alternate  ground-return  during  self-test. 1-19. Discrete Signal Monitor Programs. (See  FO-3  and  FO-8.  Refer  to  table  1-2.) a.  Program  No.  1.   Selected  for  monitoring  CYCLIC  MAG  BRAKE  ON,  CLTV  MAG  BRAKE  ON, SWIVEL  LOCKED,  and  AFCS  ENGAGE  ON  signal  functions  for  +28  volt  dc  or  open  circuit.  Program 1  uses  the  ac/dc  amplifier,  programmable-gain  amplifier  (gain  –1.0),  and  threshold-detector. (1)  An  active-low  signal  on  this  input  line  is  applied  to  matrix  inputs  U7-11  and  U7-1.  This causes  electronic-switch  sections  U11-6,  8,  9  and  U14-13,  1,  2  to  turn  on.  It  allows  electronic-switch  sec- tions  U11-5,  4,  3  and  14-6,  8,  9  to  be  activated. (2)  U11-8,9  contacts  connect  resistor  R62  to  logic  ground.  This  provides  a  O  volt  dc  input  level  to the  ac/dc  amplifier  when  the  +28  volt  dc  signal  is  inactive  (open  circuit).  U1  1-473  contacts  bypass  the ac to dc converter. (3) U14-1,  2  contacts  connect  the  output  of  the  ac/dc  amplifier  to  the  programmable-gain  am- plifier  thru  resistor  R78. (4)  U14-8,  9  contacts  bypass  the  offset/inverter  amplifier. b.  Program  No.  2.  Selected  for  monitoring  L  ROLL  BEEP  TRIM  ON  and  R  ROLL  BEEP  TRIM ON  signal  functions  for  13  volts  ac  or  open  circuit.  Program  2  provides  an  ac  mode  signal  for  the  dmm. It  uses  the  ac/dc  amplifier,  ac  to  dc  converter,  programmable-gain  amplifier  (gain  -1.92),  and threshold-detector. (1)  An  active-low  signal  is  applied  to  matrix  inputs  U7-13,  U8-12,  and  U10-1.  This  causes electronic switch sections U11-6, 8, 9, U11-U13, 1, 2 and U12-6, 8, 9 to turn on. It also causes section U11-5,4,  3  to  turn  off,  and  allows  electronic-switch  section  U14-6,  8,9  to  be  activated.  Transistor  Q5  is turned  on to  energize  relay  K3.  Relay  K3  connects  an  ac  mode  level  to  the  METER  SOURCE  switch. When  the  METER  SOURCE  switch  is  set  to  DISCRETE  MON,  the  dmm  displays  the  ac  signal. (2)  U11-8,9  contacts  connect  resistor  R62  to  logic  ground.  This  provides  a  O-volt  dc  input  level  to the  ac/dc  amplifier  when  the  13  volt  ac  signal  is  inactive  (open  circuit). (3) U11-4,3  contacts  open.  This  opens  the  bypass  around  the  ac  to  dc  converter. 1-7

Aviation News
Manned and Unmanned Systems: Polish Students and Lockheed Martin Collaborate
[Avionics Today 08-29-14] In a partnership with Lockheed Martin, a...
aviationtoday.com
Rockwell Collins do Brazil Expanding San Jose dos Campos Facilities
Rockwell Collins headquarters Photo: Rockwell Collins [Avionics Today 08-29-14] Rockwell...
aviationtoday.com
Aegean Airlines adds two additional aircraft to its previous A320ceo order
Now seven new aircraft to join the all-Airbus single aisle...
airbus.com
IAE V2500-E5 Engine Receives KC-390 Certification
The fan of an IAE V2500 Engine. Photo: Wikipedia [Avionics...
aviationtoday.com
Through Clutter or Gunfire: Northrop Grumman’s CIRCM Completes Rigorous Testing
A Northrop Grumman CIRCM. Photo: Northrop Grumman [Avionics Today 08-28-2014]...
aviationtoday.com
Indian Defence Ministry Bans Finmeccanica From Bidding
Although still conducting its investigation into whether senior managers from...
aviationtoday.com
CAE New Flight Simulator Demonstrates Interoperability, Networking
CAE demonstrates simulation interoperability and networking for RAAF C-130J aircrews....
aviationtoday.com
United Nations Mi-8 Downed in Sudan 
The Russian operator of a United Nations chartered Mi-8 helicopter...
aviationtoday.com
AMTC Keynote Speakers Announced
The Air Medical Transport Conference (AMTC) is less than a...
aviationtoday.com
RQ-4 Global Hawk UAS Proves Expanded Mission Capabilities
A Northrop Grumman RQ-4 Global Hawk. Photo: Wikipedia [Avionics Today...
aviationtoday.com
Beechcraft Delivers to Mexican Navy
Beechraft delivering the T-6C+ aircraft to the Mexican Navy. Photo:...
aviationtoday.com
Pilatus Partners with TASL for PC-12 Assembly
A Pilatus PC-12 in flight. Photo: Pilatus [Avionics Today 08-25-2014]...
aviationtoday.com
Lockheed Martin’s F-35 on Steady Path to IOC
An F-35B aircraft. Photo: Lockheed Martin [Avionics Today 08-25-2014] The...
aviationtoday.com
GE Looks to Lower H Series Fuel Costs
An H80 powered L-410 aircraft. Photo: GE [Avionics Today 08-22-2014]...
aviationtoday.com
MD 530G Shows Its Muscles at Yuma
The MD 530G scout attack helicopter has just completed its...
aviationtoday.com
XTAR and Leidos Team Up to Test AISR
[Avionics Today 08-21-2014] XTAR, LLC signed an agreement with Leidos,...
aviationtoday.com
Unmanned Air, Ground Vehicles Aid Army Mission
An autonomous resupply, reconnaissance, surveillance and target-acquisition demonstration was been...
aviationtoday.com
Lockheed Martin Readies F-16V for Taiwan Launch
A U.S. Air Force F16 in Flight. Photo: Wikipedia [Avionics...
aviationtoday.com
Pilatus Provides a Better View with New EVS
Pilatus PC-12 EVS Sensor. Photo: Pilatus [Avionics Today 08-19-2014] Pilatus...
aviationtoday.com
Manned and Unmanned Systems: Expanding Integration
 X-47B UAS taking off from a carrier in the Eastern...
aviationtoday.com

 


Privacy Statement - Copyright Information. - Contact Us

comments powered by Disqus

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +