Elenco's PK-201 Experiment #42: One-shot

A variation of the astable multivibrator circuit that is called a one-shot multivibrator, because the LED comes on once each time the switch is turned on. The 33k ohm and variable resistor with the 100 microfarad capacitor control how long the LED is on. In the beginning of the video, the LED is on for a few seconds and then goes out. I increase the resistance of the variable resistor and the LED stays on longer.

 

 

Circuit

 

Elenco's PK-201 Experiment #41: Noisy Blinker

Similar circuit configuration as last experiment (Astable Multivibrator). When the switch is turned on, the LED lights and one hears sound from the speaker. Turning the variable resistor and the frequency of the sound changes. The LED appears to be solid bright then dim but is blinking about 500 times a second (due to the small disc capacitors). In the second video, I replace the disc capacitors with the 100 and 10 microfarad capacitors to make the frequency rate much lower.

 

 

Circuit

 

Elenco's PK-201 Experiment #40: Blinking Lights

This experiment is a circuit configuration of an oscillator called Astable Multivibrator. In this type of oscillator there is no inductor, the frequency is controlled only by the resistors and capacitors. One of the two transistors is always on, hence one LED is always on. The left transistor (left-LED) is controlled by the 100k ohm resistor and 10 microfarad capacitor. The right transistor (right-LED) is controlled by a 3.3k ohm resistor, variable resistor (0-50k ohm), and 100 microfarad capacitor. If the variable resistor is turned up to 50k ohms, the right LED will stay on longer than the left one. Because the capacitor's discharge time is being manipulated, with the variable resistor.

 

 

Circuit

 

Elenco's PK-201 Experiment #39: Fun with Water

This is the same oscillator circuit used in Experiments #36..38; in addition, same resistance principle's of Experiment #7 and #20. This experiment shows how impurities can lower resistance. And that one's body, has a higher resistance to electrons than water or salt water. In each case, the resistance is lowered and the frequency rate increases. To conclude, adding impurities makes it easier for electrons to flow through semiconductors.

 

 

 

Elenco's PK-201 Experiment #38: Electronic Keyboard

Same oscillator circuit and principle's as Experiments #36 and #37. But, with a different shape that is connecting various circles that produce different pitches in sound, like notes. I try each circle (key) twice than I try and play "Mary Had a Little Lamb". 

 

Circuit

 

Elenco's PK-201 Experiment #37: Electronic Kazoo

This experiment is the same oscillator circuit and principle's of resistance in Experiment #36. But, using a pencil to create a different shape, hence a little different frequency of sound.

 

 

 

Elenco's PK-201 Experiment #36: Drawing Resistors

Here in this experiment, I am using the same basic oscillator circuit; in addition, pencil carbon to create different types of drawn resistors -- to change the frequency rate to make different sounds. By making the drawn resistors longer should increase the resistance (resistors in series); more over, making the drawn resistors wider should reduce the resistance (resistors in parallel).

 

Circuit