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

,

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

Elenco's XP-720K Power Supply Kit

The XP-720K power supply features three solid-state DC supplies. Two DC supplies are positive and negative 1.25 - 15 volts at 1 ampere. The third has a fixed 5 volt at 3 amperes. There is one integrated circuit regulating each DC supply for a total of three integrated circuits. In addition, the supply has two 6.3 volts alternating current supplies that are taken directly from the transformer; moreover, the transformer steps down the 120VAC input to 17VAC, which is delivered to the AC to DC converter. This converter consists of two diodes and a 2200 microfarad capacitor. To conclude, this supply was fun to build and is about all I would need on my work bench. I think any lab or work bench would find it useful. Lastly, I like the small profile and the look of the control panel. Below are the assembly pictures, and the testing information for the power supply. I also included the watt reading's of the supply during the testing phase.  

 Assembly

Heat sink with IC and transistor

PC Board completed 

Transformer wired to fuse and switch

PC Board wired into Transformer, Binding Posts, Potentiometers, ICs, and Transistor

Completed XP-720 Power supply. 

Testing

Testing the Positive Variable DC 1.25-15V low end

Testing the Positive Variable DC 1.25-15V high end

Testing the Negative Variable DC -1.25- -15V low end

Testing the Negative Variable DC -1.25- -15V high end

Testing the 5VDC 

Testing first post 6.3VAC

Testing second post 6.3VAC

 LOAD TEST #1

The first test is to set the voltage at 10V and connecting a 10 ohm, 10 watt resistor from the output to ground. The output should not change more than 0.20 V. The results was a change of - 0.13 --acceptable. The watt reading was not part of the testing, but I recorded how many watts the power supply draws from the outlet, which was 37.7 watts.  

Dialed in load test voltage for 10 ohm, 10 watt resistor

Load tested at 9.88VDC 

 LOAD TEST #2

The second and last load test was the 5VDC. This test required connecting a 2.5 ohm, 12 watt resistor from the output to ground. The output should not change more than 0.20V. 

The result was a change of - 0.11 --acceptable. And the watt reading was 37.2.

Reading before load test of 2.5 ohm, 12 watt resistor

Load tested at 4.84VDC

Elenco's PK-201 Experiment #50: Logic Combination

This is the last circuit of the first part (PK-101) of the PK-201 course. This circuit is a combination of some of the other digital gates. There is one output that uses a LED, and three inputs X is the red wire, Y is the blue wire, and Z is the green wire. In the video, I show the work book's truth table, I then demonstrate the experiment then I return to the truth table before cutting. The pictures below are the circuit and the schematic out of the work book.  

I believe this is an OR gate that is connected to a third transistor acting as an electronic on/off switch. The transistor is turned on using the green wire or the Z input. Because the LED only lights when Z is connected to the 9v input with either the X and/or Y input connected to 9v input.

Circuit

Schematic Experiment #50