The AM Forum
October 08, 2024, 08:11:54 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: Parallel mosfets  (Read 8309 times)
0 Members and 2 Guests are viewing this topic.
VE3LYX
Member

Offline Offline

Posts: 763


Crystals are from the stone age


WWW
« on: September 17, 2018, 11:28:49 AM »

This may be a dumb question but         so adding mosfets in parallel adds the ability to switch higher currents without fet damage but other then a slight drop in resistance does not add power as would happen when amplifying rathr then switching?
Don
Logged

Don VE3LYX<br />Eng, DE & petite Francais
PA0NVD
Member

Offline Offline

Posts: 615


Nico and Chappie (Chappie is the dog...)


« Reply #1 on: September 17, 2018, 12:46:29 PM »

If you can switch twice the current, you have twice the power, but the load resistance should be 2 timers lower. When you don't lower the load resistance, the FET's swich half the current as before and the resistive ON losses are less, but hardly noticable
Logged
VE3LYX
Member

Offline Offline

Posts: 763


Crystals are from the stone age


WWW
« Reply #2 on: September 17, 2018, 02:30:27 PM »

So that would be a yes? The fets are working half as hard if everything else remains the same.
So..how do you change the load resistance in practical terms if you want to..make it grunt. 1/2 the turns on the output transformer primary or?
Logged

Don VE3LYX<br />Eng, DE & petite Francais
VE3ELQ
Contributing
Member
*
Offline Offline

Posts: 258


« Reply #3 on: September 17, 2018, 05:58:54 PM »

So that would be a yes? The fets are working half as hard if everything else remains the same.
So..how do you change the load resistance in practical terms if you want to..make it grunt. 1/2 the turns on the output transformer primary or?

Don, Power is square law so reducing the primary by half or doubling the secondary would double the voltage and with the same load would also double the current giving four times the power.  So change the turns by root 2 or .707 less primary or 1.414 more secondary to double the power.

73s  Nigel
Logged

A "Tube Free" zone.
VE3LYX
Member

Offline Offline

Posts: 763


Crystals are from the stone age


WWW
« Reply #4 on: September 18, 2018, 07:45:30 AM »

Tnx. I am slowly beginning to comprehend this. I have a lash up.working but not yet comfortable. Driving was my obstacle but I got it working. I also suffer from toroiditess. Hosever there is hope.
Don
Logged

Don VE3LYX<br />Eng, DE & petite Francais
VE3ELQ
Contributing
Member
*
Offline Offline

Posts: 258


« Reply #5 on: September 18, 2018, 08:43:22 AM »

Tnx. I amslowly beginni g tocomprehend this. I have a lash up.working but not yet comfortable. Driving was my obstacle but I got ut worki g. I also suffer from toroiditess. Hosever there is hope.
Don
OK Don good fun stuff.  Good drivers are as important as good FETs.  I have a bunch of IXDD614s in both TO220 and DIP8 format that you can have to play with as I will never be using them. Not the best drivers in the world but they will work. You and Linda come over for coffee or I can mail them.

73s  Nigel
Logged

A "Tube Free" zone.
VE3LYX
Member

Offline Offline

Posts: 763


Crystals are from the stone age


WWW
« Reply #6 on: September 18, 2018, 10:16:30 AM »

We will stop on.our next Kingston adventure. Ill double check before we show up.
The other morning when you were on talking with the group.on.3885 I had a portable on here. I set it on  the floor and Radio was over checking it out. I think she recognized the voice.
Logged

Don VE3LYX<br />Eng, DE & petite Francais
Pages: [1]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone © 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.05 seconds with 19 queries.