| Author | Message | ||
     Anonymous |
Whats diffrent about a photoflash capacitor that allows it do dump all its charge so much faster than a regular capacitor? | ||
| Simon Quellen Field (Sfield) |
It has a lower internal resistance. | ||
| Anonymous |
So by adding impurities that raise the resistance the people that manufacture capacitors can regulate how fast its discharged? How come capacitors arent rated in discharge time too? | ||
| Simon Quellen Field (Sfield) |
It isn't about adding impurities. It is about materials and construction that optimize for low resistance instead of high capacitance or low leakage current or cost or size. The discharge time depends on the capacitance and the resistance in the circuit. It is easy to calculate from published specifications, but cannot be known without knowing details of the circuit the user plans to use. | ||
| David Bene (Unregistered Guest) Unregistered guest Posted From: 71.111.66.227 |
Dear Mr. or Mrs. SciToys: I am scheming. --In the woods and away from normal AC power I want to dump many amps in a few milliseconds into a solenoid to cause a single but later repeatable solenoid action...repeatable like every few minutes or so. --The solenoid I am experimenting with is 3 ohms and rated for 6 vdc continuous, but I have zapped it with an undetermined current with a 1/2 wave rectified 120 VAC line for a few hundred ms., and it does what I need (that's probably over-kill in the power dept.) --I am thinking I can use a car battery into a small 12vdc to 120vac converter (75 Watt), rectify the 120vac, and charge a capacitor (or bank of them) (photoflash caps?) in a few seconds or a minute or so to do the same thing. --I believe that if both my pulse width is short and my duty cycle is low I can: 1) charge the caps fully, and, 2) not damage the solenoid by the over-voltage and/or over-heating. What do you think? 1) Do I necessarily need "photoflash" caps for this application? 2) What capacity would one need to provide maybe 20-40 amps at 120vdc? 3) Is there a quicker/easier, and perhaps more elegant way to do this? iam@pmug.org...please do not use this email address except for this thread. David B. | ||
| David Bene (Unregistered Guest) Unregistered guest Posted From: 71.111.66.227 |
Dear Mr. or Mrs. SciToys: I am scheming. --In the woods and away from normal AC power I want to dump many amps in a few milliseconds into a solenoid to cause a single but later repeatable solenoid action...repeatable like every few minutes or so. --The solenoid I am experimenting with is 3 ohms and rated for 6 vdc continuous, but I have zapped it with an undetermined current with a 1/2 wave rectified 120 VAC line for a few hundred ms., and it does what I need (that's probably over-kill in the power dept.) --I am thinking I can use a car battery into a small 12vdc to 120vac converter (75 Watt), rectify the 120vac, and charge a capacitor (or bank of them) (photoflash caps?) in a few seconds or a minute or so to do the same thing. --I believe that if both my pulse width is short and my duty cycle is low I can: 1) charge the caps fully, and, 2) not damage the solenoid by the over-voltage and/or over-heating. What do you think? 1) Do I necessarily need "photoflash" caps for this application? 2) What capacity would one need to provide maybe 20-40 amps at 120vdc? 3) Is there a quicker/easier, and perhaps more elegant way to do this? David B. | ||
| Troy (Pharoah) Intermediate Member Username: Pharoah Post Number: 25 Registered: 3-2006 |
The difference between a photoflash capacitor and a regular capacitor is that a photoflash will shock the s**t out of you if you're curious, take apart a camera, and don't discharge it! |
