Transistor "latch" circuit?

[Anonymous]

Anyone know of a simple transistor circuit to be used in place of a latching relay, to indicate the position of a turnout, and thus turning on an LED. That is, the momentary switch for the turnout activates a "continous on" for the LED. Hopefully, it's less expensive than a latching relay. I'm wondering if I explained this very well![8D]

[Anonymous]

Anyone know of a simple transistor circuit to be used in place of a latching relay, to indicate the position of a turnout, and thus turning on an LED. That is, the momentary switch for the turnout activates a "continous on" for the LED. Hopefully, it's less expensive than a latching relay. I'm wondering if I explained this very well![8D]

[Anonymous]

Can be done with transistors and resistors, but easier and cheaper to use digital logic. Choice of logic family based on your available filtered DC supply voltage. Use a flipflop, or cross coupled NAND or NOR gates. The LEDs are powered through a series resistor from power supply to a logic 0 at the output of the gates.

[Anonymous]

Can be done with transistors and resistors, but easier and cheaper to use digital logic. Choice of logic family based on your available filtered DC supply voltage. Use a flipflop, or cross coupled NAND or NOR gates. The LEDs are powered through a series resistor from power supply to a logic 0 at the output of the gates.

[Anonymous]

One more thing to be careful of - the coil in the turnout motor generates a large voltage spike when it's current is shut off. This spike can kill transistors or logic gates if not supressed to a safe level.

[Anonymous]

One more thing to be careful of - the coil in the turnout motor generates a large voltage spike when it's current is shut off. This spike can kill transistors or logic gates if not supressed to a safe level.

[Anonymous]

http://home.cogeco.ca/~rpaisley4/ToggleTwin.html showswhat you want I think...FRED

[Anonymous]

http://home.cogeco.ca/~rpaisley4/ToggleTwin.html showswhat you want I think...FRED

[Anonymous]

QUOTE: Originally posted by flee307

http://home.cogeco.ca/~rpaisley4/ToggleTwin.html showswhat you want I think...FRED

this is a great site! thanks for pointing it out Fred.

[Anonymous]

QUOTE: Originally posted by flee307

http://home.cogeco.ca/~rpaisley4/ToggleTwin.html showswhat you want I think...FRED

this is a great site! thanks for pointing it out Fred.