I used this circuit to control the solenoid valve before, but I didn't pay attention after I took over. In a recent experiment, it was found that the temperature of the tiP122 tube rose sharply after it was turned on. The solenoid valve is 24v and the built-in resistance is 18 ohms. The measured Vce is only 0.9v and Ic is 1.1A. Why is it so hot? The board has come out, do you see any help?
Wilder ポストする October 21, 2020
122 plus heat dissipation;
Jenelle ポストする October 21, 2020
The solenoid valve uses a mos tube for such a large current. Triode can also be used for small current
Brigitte ポストする October 21, 2020
First of all, good heat dissipation must be added to the three-connector, and secondly, the internal resistance of the three-connector is large, and it can work for a short time. It is recommended to change the field tube (internal resistance of milliohm level) for long-term work.
Guinevere ポストする October 21, 2020
The transistor has to withstand 1w of dissipation (heating)! ! ! Change to MOS or something else unless good heat dissipation can be ensured.
