Search found 10 matches

by jrcfg
Fri Jan 07, 2005 2:25 pm
Forum: General Discussion
Topic: Zener Diode Question
Replies: 10
Views: 2284

Re: Zener Diode Question

Thanks for the replies...actually, I want to use the 30V zener to protect a +5V regulator...the regulator has a max input of 30V. The regulator (and the circuit it supplies) are to be used in a vehicle (28V system) and I want the zener in place just in case the vehicle's voltage regulator fails high...
by jrcfg
Fri Jan 07, 2005 11:31 am
Forum: General Discussion
Topic: Zener Diode Question
Replies: 10
Views: 2284

Zener Diode Question

This is a newbie question as I am still learning...if I use a 30V zener diode and the data sheet sez it's max regulator current is 30mA, does that mean I have to use a 1K resistor in series with it to keep the current from exceeding that 30mA? (Data sheet lists absolute max Iz as Pv/Vz = 1W/30V = .0...
by jrcfg
Mon Oct 11, 2004 5:28 am
Forum: General Discussion
Topic: Bypass capacitor
Replies: 3
Views: 884

Re: Bypass capacitor

Great! Thanks very much for the good info guys.
by jrcfg
Sun Oct 10, 2004 1:25 pm
Forum: General Discussion
Topic: Bypass capacitor
Replies: 3
Views: 884

Bypass capacitor

Is it always necessary to have a bypass capacitor across Vcc & Vss when using IC's? I have a circuit which includes op amps, buffers, touch sensor IC's, and various passive components supplied by a 78M05 regulator (500mA, +5v) which has the recommended in & out capacitors (.33uF in, .1uF out). The t...
by jrcfg
Fri Sep 17, 2004 7:26 am
Forum: General Discussion
Topic: conductive traces on plastic
Replies: 4
Views: 1233

Re: conductive traces on plastic

Thanks for the tips...the Dow link was very good. Thanks again.
by jrcfg
Thu Sep 16, 2004 11:34 am
Forum: General Discussion
Topic: conductive traces on plastic
Replies: 4
Views: 1233

conductive traces on plastic

Does anyone now how conductive traces are put on plastic? Is it an inkjet or screen print process? I was considering using a silver pen and just drawing them but am not sure if it would stick or if the traces would crack or separate when I bend the plastic. (The application is a flexible sense elect...
by jrcfg
Thu Apr 22, 2004 6:26 pm
Forum: General Discussion
Topic: 556 and Flip Flop
Replies: 3
Views: 812

Re: 556 and Flip Flop

Am I making this more difficult than it needs to be?
by jrcfg
Thu Apr 22, 2004 12:21 pm
Forum: General Discussion
Topic: 556 and Flip Flop
Replies: 3
Views: 812

556 and Flip Flop

Hi folks, here's a question.... I would like to use a 556 timer to flash an LED for 8 sec then stay on. I was thinking I could use the 556, set up one side astable out through a transister and diode to the LED. The other side would be monostable with an 8 second delay to pulse a 4027 flip flop which...
by jrcfg
Sun Apr 18, 2004 10:41 am
Forum: General Discussion
Topic: Volt sensor with flashing LED
Replies: 4
Views: 1046

Re: Volt sensor with flashing LED

Thanks for the suggestion...I'll have to try the 339 op amp. RussK sent me a latching circuit which I added to my breadboard today and tested with my circuit. Works great. My circuit also uses an 8v regulator for a reference voltage which is adjusted with a pot. Will have to tear it all apart and tr...
by jrcfg
Wed Apr 14, 2004 7:28 am
Forum: General Discussion
Topic: Volt sensor with flashing LED
Replies: 4
Views: 1046

Volt sensor with flashing LED

Like so many others in this forum, I am just learning electronics...bought components, power supply, breadboards, books, etc. I have built a low voltage sensing circuit using a 741 op amp which triggers a flashing LED circuit (2 transistor). The circuit works well, triggering at 12.8V (normal voltag...