User:Anna Pfannstiel

32 editsJoined 29 July 2015

Introduction to Electronics

Assignment 1: variable resistance and conductivity

555 timer in astable mode with speaker and different conductive materials

Current flows through the 555 timer circuit and the attached conductive material, which creates square wave oscillations that are output on a speaker.


<videoflash type="vimeo">134547338|400|265</videoflash> <videoflash type="vimeo">134555309|400|265</videoflash>

By changing conductive material(water, metal..), you change the resistance and the pitch of the tone.

schematic for 555 timer in astable mode with speaker and different conductive materials

555 astable 2 small.jpg

Assignment 2: momentary switch

switch, relay, motors 555 timer, 2 switches, relay, 2 motors, trash


<videoflash type="vimeo">136196422|400|265</videoflash>


The first momentary switch is connected to the power supply of the circuit. By pushing the cardboard-button, the inside alu foil is touching alu foil and closes the circuit, the motors are on/off.

The second momentary switch works the same way, but is connected to a DPDT-relay. When metal touches metal the polarity reverses which changes the direction of the attached motors.