Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
johnl69 said:Can a Transistor be used as a N/C switch so that it allows current to pass when there is no current at the base?
killivolt said:Does it need a resistor or does the Jfet provide the resistance ?
Hero999 said:That won't work.
Notice, that I said that JUGFETs reuquire a negative voltage to turn off so you need to reverse the battery connected to the gate.
Also, you haven't included a series resistor so the LED will be toast.
How much current does the bulb draw?
JUGFETs tend to be low power devices which will be overloaded by the bulb.
Roff said:What are the voltage and current requirements of your relay coil?
In your schematic, which needs some help, it looks like D3 is on when the motor is on, not D1.
Do you really need all 3 LEDs?
If the relay and D3 are energized when the motor is running, then SW1 will be closed, not open as you said. Am I confused, or are you? If it's me, I apologize. If it's you, why don't you try to restate the problem?johnl69 said:If I turned the battery connected to the gate around wouldnt it short out?(I am planning on using 1 supply.
I am not turning a bulb on its a relay that I am switching I just did that simple diagram the one below is what im building,
what should happen is;
For the motor to turn sw1 and sw3 need to be open and sw2 to be closed, if any of the switch is in a different postion(open when it should be closed) the motor will stop and an LED will light turn on, except for D3 which turns on when the motor is running.
I am trying to make this with the minimum amount of component.
Roff said:If the relay and D3 are energized when the motor is running, then SW1 will be closed, not open as you said. Am I confused, or are you? If it's me, I apologize. If it's you, why don't you try to restate the problem?
killivolt said:Doesn't he have to control the back emf so that the low voltage circuit will be uneffected if this is an a/c motor ?
You can use the circuit below if you don't absolutely have to have D1 and D2.johnl69 said:Your right its me that got confused (it was late)
I'll start again;
for the motor to run SW1 and SW3 need to be closed and SW2 needs to be open,
when SW1 is open the motor stop and all lights are out,
when SW2 is closed the motor stops and D2 is lit,
when SW3 is open the motor stops and D1 is lit,
Edit; D1/D2 are removed fromm the drawing below any ideas of where to connect them?
SW1 SW2 SW3 D1 D2 D3 Motor
O O O off off off off
O O C off off off off
O C O off off off off
O C C off off off off
C O O on off off off
C O C off off on on
C C O on on off off
C C C off on off off
SW1 SW2 SW3 D1 D2 D3 Motor
O O O on off off off
O O C off off off off
O C O on on off off
O C C off on off off
C O O on off off off
C O C off off on on
C C O on on off off
C C C off on off off
The voltage drop of the LED would also allow the transistor to turn on, which is not what you want.johnl69 said:If I put an LED in series with SW2(between SW2 and ground) would that then light up when the switch is in the close position.