Hello. I'm trying to use a NOT gate to power a LED and an Oscillator when the transistor's base doesn't recieve voltage. I attached an image with the circuit. The circle with T is a thermostat. The problems are:
1) The whole thing is powered at 12v. A NOT gate needs a resistance at the collector. The oscillator is made for 12v drawing 14mA. But because of the resistance the voltage drops and the oscillator doesn't recieve 12v. That means the resistance has to be small.
2) A small resistance means that a great amount of current will flow through the transistor in the saturation mode. But as I understood, in saturation mode common-emitter resistance is very small so why do my transistors heat up?
Please suggest me some type of transistor and the values of base and collector resistors to maximixe the oscillators voltage and to make the transistor stable. Or if there's another method to turn on the Oscillator and LED when the thermostat gets off then please suggest it.
Thank you
1) The whole thing is powered at 12v. A NOT gate needs a resistance at the collector. The oscillator is made for 12v drawing 14mA. But because of the resistance the voltage drops and the oscillator doesn't recieve 12v. That means the resistance has to be small.
2) A small resistance means that a great amount of current will flow through the transistor in the saturation mode. But as I understood, in saturation mode common-emitter resistance is very small so why do my transistors heat up?
Please suggest me some type of transistor and the values of base and collector resistors to maximixe the oscillators voltage and to make the transistor stable. Or if there's another method to turn on the Oscillator and LED when the thermostat gets off then please suggest it.
Thank you