1. Home
  2. Electronics Design
  3. switching Vss with a transistor

switching Vss with a transistor

Total hobbyist here.

Is there anyway to wire a transistor so that it closes the Vss instead closing the connection to ground?

I have a ciruit like this

Vss --------R1----+------------+ | | 3000 uF LED | | gnd --------------+-------------+

The capacitor provides a nice fade when Vss is switched off which is much more cool than just blinking.

So i need to wire this into the output of a sound actuation circuit (already done). But in order for the sound actuation circuit to drive the heavier load (100s of LEDs), I added a transistor.

Vss --------R1----+------------+ | | 3000 uF LED | | gnd---T1 ---------+------------+ | +5V in

This is how I see it done in my books and online

formatting link
but the problem is that the LED never gets the current bleed from the capacitor because the transistor switched off connection to ground. The other way around would work:

+5V in | Vss ----T1--R1----+------------+ | | 3000 uF LED | | gnd-----------------+------------+

But the transistor I'm using doesn't seem to want to work in this configuration.

Any ideas?

Reply to
bryanwilkerson
Loading thread data ...

Use a load switch.

Reply to
linnix 

--
First, when you\'re drawing ASCII schematics, use a non-proportional
font like Courier and _never_ use the TAB key, use the space bar.

Second, try this: (View in Courier)


            +V
             |
            [R]
             |
             +-----+
             |A    |+
           [LED] [BFC]
             |     | 
             +-----+
             |
             C
ACT>--[R]--B NPN
             E
             |
            GND


But, _hundreds_ of LEDs???
Reply to
John Fields

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.