HyperPhysics 
http://hyperphysics.phy-astr.gsu.edu/hbase/hph.html

"This site was honored because of its comprehensive coverage of most of physics, the creative use of multimedia and linking, and the impact it has had on students worldwide. Online tutorials cover a wide range of physics topics, including modern physics and astronomy. Material is organized through extensive concept maps."


[ add comment ]   |  [ 0 trackbacks ]   |  permalink
Astable  
http://www.falstad.com/circuit/#%24+1+5 ... 0+100.0%0A

[ add comment ]   |  [ 0 trackbacks ]   |  permalink
simplified astable multivibrator circuit (not working) 


this circuit does not work, but could be benefical to understand the roles of two branches which leads between capacitor and base of transistor.


[ add comment ] ( 1 view )   |  [ 0 trackbacks ]   |  permalink
astable multivibrator circuit (aka led flasher) 
http://www.falstad.com/circuit/#%24+1+5 ... 25+0+-1%0A

astable multivibrator circuit acting as a led flasher. data for simulation java applet http://www.falstad.com/circuit/ . led is expected to be about 2.5v, 20 mA and power dc supply 9v battery. not tested in real!



$ 1 5.0E-6 5.934295036739208 50 2.0 50
v 384 64 336 64 0 0 40.0 5.0 0.0 0.0 0.5
t 288 208 320 208 0 1 -4.184713778629777 0.13619941217392795 100.0
t 128 208 96 208 0 1 0.6154526523446024 0.6523326150314848 100.0
c 176 208 144 208 0 1.0E-5 4.1739553582352125
c 240 208 272 208 0 1.0E-5 -0.6046942319500379
w 288 208 272 208 0
w 128 208 144 208 0
w 320 288 96 288 0
w 96 224 96 288 0
w 384 288 384 64 0
w 320 64 320 112 0
r 320 112 320 144 0 350.0
w 96 64 96 112 0
r 96 112 96 144 0 350.0
w 96 144 96 192 0
w 336 64 320 64 0
w 320 144 320 192 0
w 240 208 96 144 0
162 320 224 320 288 1 2.1024259 1.0 0.0 0.0
w 320 288 384 288 0
w 176 208 320 144 0
w 96 64 208 64 0
w 208 64 320 64 0
r 208 64 128 208 0 2000.0
r 208 64 288 208 0 2000.0


[ 41 comments ] ( 31 views )   |  [ 0 trackbacks ]   |  permalink
Basic astable multivibrator circuit 
Below is a export of basic astable multivibrator circuit for http://www.falstad.com/circuit/ . The resistor and capacitor values are just by eye so in real this circuit might have problems.

$ 1 5.0E-6 0.34903429574618416 50 2.0 50
v 384 64 336 64 0 0 40.0 5.0 0.0 0.0 0.5
t 288 208 320 208 0 1 0.6426223132462627 0.6640109176265421 100.0
t 128 208 96 208 0 1 -3.994528534287322 -0.14567302984614652 100.0
c 176 208 144 208 0 1.0E-5 0.1670616342264259
c 240 208 272 208 0 1.0E-5 3.1848445868146333
w 288 208 272 208 0
w 128 208 144 208 0
w 320 288 96 288 0
w 320 224 320 288 0
w 96 224 96 288 0
w 320 288 368 288 0
w 384 288 384 64 0
w 256 64 176 64 0
w 176 64 144 64 0
w 320 64 320 112 0
w 128 64 128 112 0
r 128 112 128 144 0 1000.0
r 320 112 320 144 0 350.0
w 96 64 96 112 0
r 96 112 96 144 0 350.0
w 96 144 96 192 0
w 336 64 320 64 0
w 304 64 320 64 0
w 320 144 320 192 0
w 368 288 384 288 0
w 128 208 128 144 0
w 272 208 272 144 0
r 272 112 272 144 0 1000.0
w 272 64 272 112 0
w 144 64 128 64 0
w 128 64 96 64 0
w 256 64 272 64 0
w 304 64 272 64 0
w 176 208 320 144 0
w 240 208 96 144 0


[ add comment ] ( 3 views )   |  [ 0 trackbacks ]   |  permalink
Electronic circuit simulator 
http://www.falstad.com/circuit/
This java applet is an electronic circuit simulator. When the applet starts up you will see an animated schematic of a simple LRC circuit. The green color indicates positive voltage. The gray color indicates ground. A red color indicates negative voltage. The moving yellow dots indicate current.

http://www.ohmpie.com/hm555/
Home made 555 timer from NPN and PNP transistors

http://talkingelectronics.com/projects/ ... cuits.html
Save 50 - 555 Circuits (more than 97 Circuits) as: .doc (2.1MB) or .pdf (1.4MB) (26-5-2011)

http://www.electronics-tutorials.ws/wav ... table.html
Regenerative switching circuits such as Astable Multivibrators are the most commonly used type of relaxation oscillator as they produce a constant square wave output waveform as well as their simplicity, reliability and ease of construction.

[ 8 comments ] ( 1 view )   |  [ 0 trackbacks ]   |  permalink
Resistor colour codes 
http://www.csgnetwork.com/resistcolcalc.html

[ add comment ] ( 1 view )   |  [ 0 trackbacks ]   |  permalink
Zeman odstartoval kampaň útokem na vládu 


[ add comment ] ( 7 views )   |  [ 0 trackbacks ]   |  permalink
NFSv4 GSS_API "support" 
NFSv4 "supports" the following security mechanisms

NFSv4 using AUTH_SYS
NFSv4 using AUTH_GSS (Kerberos 5)
NFSv4 using AUTH_GSS (SPKM-3)*
NFSv4 using AUTH_GSS (LIPKEY)*
NFSv4 Name to ID mapping

http://www.citi.umich.edu/projects/nfsv4/linux/faq/


GSS_API - Generic Security Services Application Program Interface
http://en.wikipedia.org/wiki/Generic_Se ... _Interface

SPKM - Simple Public-Key GSS-API Mechanism (SPKM)
http://tools.ietf.org/html/rfc2025

*GSS-API mechanism which is based on a public-key, rather than a symmetric-key, infrastructure

[ 7 comments ] ( 1 view )   |  [ 0 trackbacks ]   |  permalink
Kerberos: extend the ticket lifetime and make ticket renewable 
TGT renewal might be useful for long running job which mounts NFS/RKB share.

- max_life and max_renewable_life in /var/kerberos/krb5kdc/kdc.conf on the KDC servers as in shipped example /usr/kerberos/share/examples/krb5/kdc.conf (if you do use CentOS/RHEL)

[kdcdefaults]
kdc_ports = 750,88

[realms]
ATHENA.MIT.EDU = {
database_name = /usr/local/var/krb5kdc/principal
admin_keytab = FILE:/usr/local/var/krb5kdc/kadm5.keytab
acl_file = /usr/local/var/krb5kdc/kadm5.acl
key_stash_file = /usr/local/var/krb5kdc/.k5.ATHENA.MIT.EDU
kdc_ports = 750,88
max_life = 10h 0m 0s
max_renewable_life = 7d 0h 0m 0s
}


- ticket_lifetime in /etc/krb5.conf on the client machine

[libdefaults]
default_realm = REALM
dns_lookup_realm = false
dns_lookup_kdc = false
forwardable = yes
ticket_lifetime = 32d
renew_lifetime = 32d


- maxlife for the user and krbtgt/REALM principal


kadmin: modprinc -maxlife 32days -maxrenewlife 32days +allow_renewable krbtgt/REALM
kadmin: modprinc -maxlife 32days -maxrenewlife 32days +allow_renewable user/REALM


- output of the getprinc for user

kadmin:  getprinc USER
Principal: USER@REALM
Maximum ticket life: 32 days 00:00:00
Maximum renewable life: 32 days 00:00:00


- maxlife for the service principal "krbtgt/REALM"

kadmin:  getprinc krbtgt/domain.com@REALM
Maximum ticket life: 32 days 00:00:00
Maximum renewable life: 32 days 00:00:00


- request extended lifetime and renewal in the ticket request
$ kinit -l 14d -r 14d


- to renew the ticket, use the kinit -R option before the ticket expires
$ kinit -R


links:

http://linsec.ca/Using_Kerberos_5_for_S ... entication

k5start and krenew are modified versions of kinit which add support for running as a daemon to maintain a ticket cache, running a command with credentials from a keytab and maintaining a ticket cache until that command completes, obtaining AFS tokens (via an external aklog) after obtaining tickets, and creating an AFS PAG for a command. They are primarily useful in conjunction with long-running jobs; for moving ticket handling code out of servers, cron jobs, or daemons; and to obtain tickets and AFS tokens with a single command.


[ 6 comments ] ( 2 views )   |  [ 0 trackbacks ]   |  permalink

<<First <Back | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | Next> Last>>