I am a novice, trying to make a simple circuit for a motion sensor closet light. What I did works, but I need to make it brighter to be useful. This ought to be simple, but it's stumping me.
The working circuit that is not bright enough uses a 12V battery, a 7W LED light bulb, and an HC-SR501 motion sensor. The 12V battery, if connected directly to the bulb, is plenty bright. The middle pin of the HC-SR501 sends a signal to the transistor when motion is detected, which then enables the current to light the light. But I had to add a 33R 5W resistor to keep the transistor I first used (a BJT 2N2222) from burning up. That resistor (I think) makes the bulb too dim to be useful.
So I took out the resistor and tried replacing the transistor with a higher-voltage TIP31C, that's supposed to handle 50V. The circuit works, but the light is still too dim. The same result happens when I double the voltage to 24V. The transistor also gets extremely hot -- one began burning the wood on my workbench.
The same result happens with an FJP13009 transistor, which is supposed to handle 700V. Circuit works, but light is still dim, at both 12V and 24V. I tried sticking the 33R resistor between the battery and the transistor, but that did not change the outcome.
I also tried a Vishay IRFZ44 transistor, supposed to handle 60V, and got very strange results. The bulb would glow brightly whether or not the gate was connected. Again, the transistor got very hot. (I thought I was perhaps getting the pin connections wrong, but the only one of the six possible combinations that produced any light at all was the one where the gate pin was irrelevant.)
I'm embarrassed to admit how long I've been fiddling with this. Can someone help me? I'm now trying to learn Spice to simulate the circuit, but that's going slowly.
The working circuit that is not bright enough uses a 12V battery, a 7W LED light bulb, and an HC-SR501 motion sensor. The 12V battery, if connected directly to the bulb, is plenty bright. The middle pin of the HC-SR501 sends a signal to the transistor when motion is detected, which then enables the current to light the light. But I had to add a 33R 5W resistor to keep the transistor I first used (a BJT 2N2222) from burning up. That resistor (I think) makes the bulb too dim to be useful.
So I took out the resistor and tried replacing the transistor with a higher-voltage TIP31C, that's supposed to handle 50V. The circuit works, but the light is still too dim. The same result happens when I double the voltage to 24V. The transistor also gets extremely hot -- one began burning the wood on my workbench.
The same result happens with an FJP13009 transistor, which is supposed to handle 700V. Circuit works, but light is still dim, at both 12V and 24V. I tried sticking the 33R resistor between the battery and the transistor, but that did not change the outcome.
I also tried a Vishay IRFZ44 transistor, supposed to handle 60V, and got very strange results. The bulb would glow brightly whether or not the gate was connected. Again, the transistor got very hot. (I thought I was perhaps getting the pin connections wrong, but the only one of the six possible combinations that produced any light at all was the one where the gate pin was irrelevant.)
I'm embarrassed to admit how long I've been fiddling with this. Can someone help me? I'm now trying to learn Spice to simulate the circuit, but that's going slowly.
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