Please find attached a circuit. This circuit turns on a 500mA relay when the Th1 temperature, controlled by P1, is exceeded.
As a very beginner, I'm trying to adjust this.
Instead of the 500mA relay, I will use a 12VDC 500mA pump motor. The datasheet for the 2N2222 describes it as "designed for a high speed switching application at collector current up to 500mA". Do I need something bigger, to handle start/stop spikes?
Instead of turning on the pump when it reaches a particular temperature (65 degrees C), I want to turn it off. Is it as simple as swapping the leads going to pins 2 and 3 of the LM741?
The R2 resistor handles hysteresis. A range of 120K ohms to 470K ohms was specified. I'm okay with 1.5 degrees C during which the state does not change. Would that be the high end of the R2 range?
Thanks very much.
As a very beginner, I'm trying to adjust this.
Instead of the 500mA relay, I will use a 12VDC 500mA pump motor. The datasheet for the 2N2222 describes it as "designed for a high speed switching application at collector current up to 500mA". Do I need something bigger, to handle start/stop spikes?
Instead of turning on the pump when it reaches a particular temperature (65 degrees C), I want to turn it off. Is it as simple as swapping the leads going to pins 2 and 3 of the LM741?
The R2 resistor handles hysteresis. A range of 120K ohms to 470K ohms was specified. I'm okay with 1.5 degrees C during which the state does not change. Would that be the high end of the R2 range?
Thanks very much.