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Yes. Use a DC one that works from 3VDC to the desired node capable of driving it.
----> https://www.ecosia.org/images?q=dc piezo buzzer beeper
They should be under $2. Also canibalizable from defunct equipment.
----> https://www.ecosia.org/images?q=dc piezo buzzer beeper
They should be under $2. Also canibalizable from defunct equipment.
The circuit is not guaranteed to function, because the 741 is not rated to operate on 9 V.
Also, Q1, R6, and R8 form a very non-standard enable circuit. My guess is that this is necessary because of the severely reduced output voltage swing of the 741. Have you built this circuit, and does it actually work?
ak
Also, Q1, R6, and R8 form a very non-standard enable circuit. My guess is that this is necessary because of the severely reduced output voltage swing of the 741. Have you built this circuit, and does it actually work?
ak
I have built the circuit, but the LED does not toggle and it only stays on if a light or laser is shined on LDR 1.
When the light or laser is removed from the photocell the LED turns off.
Back to the beginning. Where did you get this circuit? Please post the document or a link to a site.
What circuit function are you are trying to achieve? To me it looks like an LED flasher circuit that is enabled when R1 has more light on it than R2.
What is your skill set for building this circuit on perf board or a solderless breadboard? Also, what other ICs do you have access to? LM358 / LM324? LM393 / LM339?
Where are you located?
ak
What circuit function are you are trying to achieve? To me it looks like an LED flasher circuit that is enabled when R1 has more light on it than R2.
What is your skill set for building this circuit on perf board or a solderless breadboard? Also, what other ICs do you have access to? LM358 / LM324? LM393 / LM339?
Where are you located?
ak
The circuit seems to be a modification of this circuit with only one LDR.
In addition, assuming your specific chip would work from + 9 V, there is another limit, namely output voltage of the 741. The same datasheet tells us that the output voltage swing of the 741 is in worst case 3 V from the supply voltage, which in case 0f a single 9 V supply means the output swings between +3 V and + 6 V (assuming >= 10 kΩ load, which is given in this circuit). Adding 0.6 V base-emitter voltage of transistor Q1 means the voltage on the trigger pin 2 of the 555 timer ic would not go below 3.6 V (worst case, lower if ther output of the 741 is better than specified).
The trigger input (pin 2) of the 555 requires < 3 V when the 555 is operated from 9 V (datasheet). As the input voltage to pin 2 of the 555 will under the above conditions not go below 3 V, the 555 will never be triggered.
An LM358 as suggested by @AnalogKid is a much better choice instead of the 741. Notethat these chips have different pinouts, you'll have to adapt the pin numbering when using anoter opamp instead of the 741.
Right. The datasheet states under recommended operating conditions: supply voltage (min) +- 10 V.
In addition, assuming your specific chip would work from + 9 V, there is another limit, namely output voltage of the 741. The same datasheet tells us that the output voltage swing of the 741 is in worst case 3 V from the supply voltage, which in case 0f a single 9 V supply means the output swings between +3 V and + 6 V (assuming >= 10 kΩ load, which is given in this circuit). Adding 0.6 V base-emitter voltage of transistor Q1 means the voltage on the trigger pin 2 of the 555 timer ic would not go below 3.6 V (worst case, lower if ther output of the 741 is better than specified).
The trigger input (pin 2) of the 555 requires < 3 V when the 555 is operated from 9 V (datasheet). As the input voltage to pin 2 of the 555 will under the above conditions not go below 3 V, the 555 will never be triggered.
An LM358 as suggested by @AnalogKid is a much better choice instead of the 741. Notethat these chips have different pinouts, you'll have to adapt the pin numbering when using anoter opamp instead of the 741.
Link to that thread - ?
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