Search found 319 matches

by sghioto
Tue Apr 03, 2018 6:11 am
Forum: General Discussion
Topic: heat sink cooling
Replies: 5
Views: 1651

Re: heat sink cooling

I don't think it would make much difference if the chassis is ventilated properly. I would prefer to draw the heat out if possible.
SG
by sghioto
Wed Mar 28, 2018 6:51 pm
Forum: General Discussion
Topic: Need help with a circuit again
Replies: 9
Views: 1931

Re: Need help with a circuit again

One other thing, I was wondering if I could put the gate of the triac with the 1k resistor instead of the led, would that trigger the triac Not in this case as the triac will be on continuous. Best solution is to use an opto-isolator. For 10 amp loads you can use the MOC3020 to drive a high current...
by sghioto
Tue Mar 27, 2018 5:23 am
Forum: General Discussion
Topic: Need help with a circuit again
Replies: 9
Views: 1931

Re: Need help with a circuit again

Easiest solution is to use a solid state relay or what they call an opto-triac. Depending on the current required a MOC3020 may be adequate.
SG
by sghioto
Thu Mar 22, 2018 3:49 pm
Forum: General Discussion
Topic: Security light motion sensors in parallel
Replies: 11
Views: 2306

Re: Security light motion sensors in parallel

You will have two dimmer circuits in parallel so as I said it may work OK or not. You would have to turn the DualBrite switch to OFF on one of the units.
SG
by sghioto
Wed Mar 21, 2018 2:50 pm
Forum: General Discussion
Topic: Security light motion sensors in parallel
Replies: 11
Views: 2306

Re: Security light motion sensors in parallel

Yeah there will be feedback through each other. The motion from one detector will override the dim function on the other. Will it cause any damage? Not sure without seeing a schematic. Can you use a two bulb fixture and run the red wires separate? Or run a 3 wire cable from the light to the junction...
by sghioto
Thu Jan 25, 2018 5:47 pm
Forum: General Discussion
Topic: Adult Content!
Replies: 6
Views: 1918

Re: Adult Content!

Man is it slow around here. :mrgreen:
by sghioto
Tue Jan 02, 2018 5:37 am
Forum: General Discussion
Topic: LM 1084/338/317/etc... voltage drop at < 1A
Replies: 23
Views: 4097

Re: LM 1084/338/317/etc... voltage drop at < 1A

Cathodes soldered together and wired to transformer's center tap . That can't be correct! The cathodes should be connected to the filter capacitors, the center tap of the transformer is connected to ground for full wave rectification However from your description of the supply voltage, 22 volts no ...
by sghioto
Fri Dec 22, 2017 3:36 pm
Forum: General Discussion
Topic: Need help with a circuit
Replies: 6
Views: 1577

Re: Need help with a circuit

Schmitt trigger circuit. Two transistors and some parts rearranged. D2 normally on. Press S1 and D2 turns off and D1 turns on and stays on for two seconds after switch is released.
Cheers and Happy Holidays,
Steve G
by sghioto
Mon Nov 27, 2017 8:42 am
Forum: General Discussion
Topic: LM1084 input voltage
Replies: 2
Views: 754

Re: LM1084 input voltage

You may be able to place a resistor in series with the output of the power supply and the input pin of the LM1084 if you know appx. the minimum and maximum current.

Steve G
by sghioto
Thu Nov 23, 2017 6:46 pm
Forum: General Discussion
Topic: Another simple amp question
Replies: 16
Views: 2027

Re: Another simple amp question

OK here's my version using two 2N3904's in a darlington configuration.
With the component values shown:
Gain = 10, load 10K
Max output = 2 volts rms before distortion begins
Current drain = .5ma
Input Impedance = 100K

Steve G
by sghioto
Mon Nov 20, 2017 5:09 am
Forum: General Discussion
Topic: Another simple amp question
Replies: 16
Views: 2027

Re: Another simple amp question

Yes it is, I was thinking of the emitter follower when I made that statement so stand corrected.

Steve G
by sghioto
Sun Nov 19, 2017 10:05 pm
Forum: General Discussion
Topic: Another simple amp question
Replies: 16
Views: 2027

Re: Another simple amp question

The problem with that circuit is the low input impedance. Guitar pickups are high impedance devices that need a high impedance input amp to work correctly which is why I suggested the op amp circuit. You don't have to etch a board, you can assemble the circuit on a small "perf" board.

Steve G
by sghioto
Sun Nov 19, 2017 5:14 pm
Forum: General Discussion
Topic: Another simple amp question
Replies: 16
Views: 2027

Re: Another simple amp question

A common emitter is not an amplifier. Why not just use a simple op amp circuit like a MCP6281?

Steve G
by sghioto
Sun Mar 26, 2017 5:41 am
Forum: General Discussion
Topic: CFL vs. LED Light Bulbs
Replies: 15
Views: 2713

Re: CFL vs. LED Light Bulbs

Depends on the light appearance number. If they are the same then the color should be similar. The ones on Ebay you mentioned are listed as 4000-4500K which is commonly called "natural white", 5000K are usually listed as "bright white".

Steve G
by sghioto
Mon Jan 09, 2017 5:12 am
Forum: General Discussion
Topic: proto builder for hire?
Replies: 4
Views: 1466

Re: proto builder for hire?

PM sent