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

 

Elenco's PK-201 Experiment #35: Electronic Noisemaker

This experiment uses a variable resistor to change the frequency of the sounds; in addition, when the switch is turned on, the capacitance of the oscillator is increased because the capacitors (.005 and .047 microfarad) are in parallel, and this lowers the oscillator frequency.

 

 

Circuit

 

Elenco's PK-201 Experiment #34: The Space Gun

This experiment is basically the same as experiment #33, except for the placement of the 10 microfarad capacitor and a disc capacitor. The variable resistor is used as before to change the sound of the gun.

 

Circuit

 

Elenco's PK-201 Experiment #33: Electronic Rain

In this experiment, a variable resistor (0 to 50000 ohms) is used to control the oscillator's frequency rate. This give the effect of electronic rain (not real world rain) pouring down at very low resistance and drizzling at very high resistance.

 

 

Circuit

 

Elenco's PK-201 Experiment #32: Siren

This experiment is using the same basic oscillator circuit introduced in experiment #28. But, the oscillator's resistance is electronically varying. The 1,000,000 ohm resistor and 10 microfarad capacitor slowly increase the base voltage (base current) on the transistor (NPN-Left). As the base current slowly increases the collector current (NPN-left) also increases slowly. The transistor (NPN-left) is now limiting the current just as a resistor does. When the switch is turned off, a similar effect occurs as the 10 microfarad capacitor slowly discharges. Note: I short the capacitor at the end to silents the siren.

 

Circuit

 



Elenco's PK-201 Experiment #31: Morse Code

This experiment uses the same oscillator circuit as used in the previous experiments. Here, a switch is used to form a telegraph. Telegraph's where widely used in the last half the the 19th century before telephone systems. Telegraph's have only two states on and off. A code called Morse Code was developed by Samuel F. B. Morse of dots and dashes (long or short transmission burst) to send message in the form of electrical current along wires for communication. 

 

 

Circuit

 

Morse Code

Elenco's PK-201 Experiment #30: The Alarm

This experiment is an oscillator circuit with a trip wire. The alarm is turned on by disconnecting a wire and turned off by connecting the wire (trip wire). The trip wire creates a "short circuit" across the transistor base, so no current flows into the base of the transistor and it stays off. When the "trip wire" is disconnected, the short is removed, and the circuit works sounding an alarm.

 

 

Circuit