Elenco's PK-201. CI-22 Experiment PC7: Electronic Sound PC

The objective of this experiment is to look at the output signal from a transistor oscillator while changing the pitch of the sound with four sets of capacitors and resistors. I will show both waveform and spectrum for each set. 

Circuit

A 0.005 microfarad capacitor with: 10K, 33K, 100K, and 1M ohm resistors. 

Waveform 10K ohm resistor

Spectrum of 10K ohm resistor

Waveform 33K ohm resistor

Spectrum 33K ohm resistor

Waveform 100K ohm resistor

Spectrum 100K ohm resistor

Waveform 1M ohm resistor

Spectrum 1M ohm resistor

A 0.047 microfarad capacitor used with: 10K, 33K, 100K, and 1M ohm resistors

  

Waveform 10k ohm resistor

Spectrum 10K ohm resistor

Waveform 33K ohm resistor

Spectrum 33K ohm resistor

Waveform 100K ohm resistor

Spectrum 100K ohm resistor

Waveform 1M ohm resistor

Spectrum 1M ohm resistor

A 10 microfarad capacitor used with: 10K, 33K, 100K, 1m ohm resistors.

Waveform 10K ohm resistor

Spectrum 10K ohm resistor

Waveform 33K ohm resistor

Spectrum 33K ohm resistor

Waveform 100K ohm resistor

Spectrum 100K ohm resistor

Waveform 1M ohm resistor

Spectrum 1M ohm resistor

A 100 microfarad capacitor used with: 10K, 33K, 100K, 1M ohm resistors.

Waveform 10K ohm resistor

Spectrum 10K ohm resistor

Waveform 33K ohm resistor

Spectrum 33K ohm resistor

Waveform 100K ohm resistor

Spectrum 100K ohm resistor

Waveform 1M ohm resistor

Spectrum 1M ohm resistor

Elenco's PK-201, CI-22 Experiment PC6: Noisy Blinker PC

The objective of this experiment is to demonstrate wait mode with multiple colors of a waveform. Wait mode in an oscilloscope scans then waits until the waveform exceeds the trigger level. Combining wait mode and storage mode with color codes allows one to compare waveform signals for analysis. 

Circuit

Waveform

Wait mode with colored waveform

Storage and wait mode with color coded waveforms

Frequency spectrum wait mode does not apply

Elenco's PK-201, CI-22 Experiment PC5: Electronic Noisemaker PC

The objective of this experiment is to demonstrate the storage mode of the oscilloscope. Storage mode in a oscilloscope allows one to view multiple scans at the same time.

Circuit

Waveform without Storage mode

Waveform with Storage mode

Frequency spectrum without Storage mode

Frequency spectrum with Storage mode

Elenco's PK-201, CI-22 Experiment PC4: Space Gun PC

The objective of this experiment is to look at the output of the space gun circuit. 

Circuit

Waveform

Frequency spectrum

Elenco's PK-201, CI-22 Experiment PC3: Siren PC

The objective of this experiment is to watch the output of a changing circuit. The pictures below are in pairs, two waveform's and two frequency spectrum's. This is done as the siren circuit is turned on and off and the capacitors discharge.

Circuit

Waveform when circuit is turned on

Waveform as circuit is turned off --capacitor discharge

Frequency when circuit is turned on

Frequency as capacitors are discharged circuit turned off

Elenco's PK-201, CI-22 Experiment PC2: Speaker Microphone

In this experiment the PC-interface cable is connected directly to the speaker, and is used to convert my voice into an electrical signal. A speaker uses electrical energy to create mechanical vibrations. These vibrations create variations in air pressure, called sound waves, that allow one's ears to feel air pressure variations and "hear". Just as in a microphone, air pressure variations can also cause a speaker to vibrate, which causes the speaker to create a small electrical signal, but not as efficiently as a microphone. In oscilloscope mode, well-rounded, smooth, and repetitive waveforms have nearly all of their energy at a specific frequency. A "square" or "rectangular" waveforms and most music have a series of mathematically-related peaks. A "random" waveform has a frequency "blob" instead of distinct peaks, for example, blowing into the speaker or several people talking at the same time.  

Speaker connected to PC-interface cable

Voice waveform at 5ms/div

Voice waveform at 0.5ms/div

Frequency spectrum at 5ms/div

Frequency spectrum at 0.5ms/div

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Elenco's PK-201, CI-22 Experiment PC1: Pitch

This experiment's focus is on introducing one with the features of Winscope. Winscope is software that simulates an oscilloscope/spectrum analyzer and is used in the eight computer interface experiments in the PK-201 kit. The Winscope software uses a cable connected to the PC microphone input socket to interface with the circuit. One will use Winscope to view the electrical signal to the speaker in this experiment's circuit. By adjusting the gain and position control features will enable one to “see” the amplitude (voltage level) of a signal, and also see voltage vs frequency of a signal; more over, by adjusting the settings on the oscilloscope, one can look at both very large and very small voltage wave forms. The pictures below the two circuits are the screen shots of each step taken in this experiment. Lastly, it has to be understood that Winscope is inexpensive and is being used here as a teaching tool. There are limitations in regards to the microphone input and measuring wave forms correctly, so in this sense accuracy can not be relied on.  

Circuit using a .047microfarad capacitor

Amplification set too high

Adjusted Amplification 1:1 mode in 5ms/div time scale

Waveform time scale changed from 5ms/div to 0.5ms/div

Trigger position level (dash far left) 

voltage vs frequency

Circuit using a 10microfarad capacitor 

voltage (amplitude) vs time

voltage vs frequency

adjusted horizontal scale