Simulate LED in LTSpice

"Dr Mitch" schrieb im Newsbeitrag news: snipped-for-privacy@e9g2000prf.googlegroups.com...

Hello,

You don't tell SPICE when a diode is on or off, you only specify model parameters.

Example.for a model specification of a LED with 20mA, 1.7V.

.model LED1 D(Is=1e-19 N=1.6 Rs=2.5 Eg=2.1)

Replace the value D of your diode in the schematic with LED1 and place the model specifications on your schematic as a SPICE-directive.

I recommend to read some text about the basics of SPICE.

Best regards, Helmut

Most likely you have miswired your actual circuit (LED wrong way around perhaps)

Also, LEDs are very long lasting when operated within their allowable parameters, but if you miswire and subject the LED to excessive current or reverse voltage, you can destroy it in much less than a second. If you did that previously, it will most likely look like an open (infintitely high resistance) to the rest of the circuit now.

"Helmut Sennewald" schrieb im Newsbeitrag news:f9cp1t$7c2$02$ snipped-for-privacy@news.t-online.com...

Hello again,

Maybe I haven't correctly understood all questions when I answered first.

Just probe the current flowing through the LED in LTspice to see whether it's "on" or "off". If a few milli-Amperes will be shown, the LED will light in a real circuit.

Best regards, Helmut

Nahhh..It can't be...I hope you don't expect to see the LED symbol to actually light up?

D from BC