View attachment 357636
In my Launch Controller I have a diode that's supposed to shunt capacitive charge of a 4700µF cap. A 1N4001 is good to 1A. Want to channel 12V through a diode and series resistor (100Ω) to quickly discharge the cap and make the launch pad safe from accidental firing of a rocket that is in the process of being armed.
There are two 100Ω resistors in parallel. One conducts only one way.
View attachment 357638
I get 12V ÷ 50Ω = 240mA. Is that right? Should be, but a cap can deliver its full charge in nearly an instant. Should I use a smaller resistor (in series with the 1N4001? Can I get away with two 50Ω resistors?

 

Hello,

The diode could be a mur820:
https://www.alldatasheet.net/datasheet-pdf/marking/1382031/LUGUANG/MUR820.html

Bertus

 

that is not complete circuit but it looks scary. i would not want to see ANY power around igniter when armed switch is off.
if using capacitor to pad the battery, i would put it before armed switch (and make power switch DPDT to discharge it quickly).

 

panic mode:see this thread for the whole schem.
https://forum.allaboutcircuits.com/...-30-seconds-goes-high-for-1-sec.208440/page-3 Post 48

 

The diode could be a mur820:
https://www.alldatasheet.net/datasheet-pdf/marking/1382031/LUGUANG/MUR820.html

Yeah, looks and tests as depicted. Thanks. I think that's it.

 

Can I use a Germanium diode in place of a 1N4001? It's only passing an output from a 4017 to a 4083 (2 in AND gate).

Why do I ask? Because I have 100 of them. How? Why? Heck if I know. At some point I was thinking about a crystal radio. Lots of things I planned but never started.

 

Hello,

Germanium diodes most times have a low maximum current.
Think of the max current as 50 to 100 mA, dependend of the type.
Try to find a datasheet of your diode.

Bertus

 

How much current would be between outputs of a 4017 to an input of a 2 in AND gate? Can't be that much.

Oh, and I did find a data sheet. alldatasheets.com had nothing. Guess it's an old and possibly outdated component.

 

Hello,

What diode do you have?
The internet archive might have old databooks.
Also bitsavers carries a lot of old databooks.

Bertus

 

In my Launch Controller I have a diode that's supposed to shunt capacitive charge of a 4700µF cap. A 1N4001 is good to 1A. Want to channel 12V through a diode and series resistor (100Ω) to quickly discharge the cap and make the launch pad safe from accidental firing of a rocket that is in the process of being armed.

Don't see the need for the diode. The cap will fully charge or discharge in appx 2.5 seconds through the 100 ohm resistor.

 

1N60G Germanium.

 

The cap will fully charge or discharge in appx 2.5 seconds through the 100 ohm resistor.

Thanks. How did you arrive at that figure? I would have no idea how to go about that. And I'm sure it's quite easy. Maybe if I learn it and practice it a few dozen times.

 

Thanks. How did you arrive at that figure? I would have no idea how to go about that. And I'm sure it's quite easy. Maybe if I learn it and practice it a few dozen times.

I used the "Capacitor Charge and Time Constant Calculator" on the AAC website.
Tap on the Menu bars and scroll down to "Tools" then "Calculators."

 

@sghioto the calculator is saying 0.470 sec. How are you coming up with approximately 2.5 sec.?

 

Hello,

There is an old thread about the 1N60:
https://forum.allaboutcircuits.com/threads/1n60-diode-is-germanium-or-silicon.171532/

Bertus

 

@sghioto the calculator is saying 0.470 sec. How are you coming up with approximately 2.5 sec.?

It takes 5 time constants to fully charge or to discharge.

 

Hello,

Here is a collection of booklets with circuits for germanium diodes and transistors:
http://n4trb.com/AmateurRadio/SemiconductorHistory/SemiconductorDocuments.htm

Bertus