Talk:Relaxation oscillator

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We need a diagram of the "classic" relaxation oscillator. Here is one in ASCII-Art, which may help. The symbols are poorly drawn, especially the neon bulb. Values are approximate; T ~ RC = 1 second (here)

 |---------|         Resistor, 100k
 | 200 V  +|---------\/\/\/--------+-----------|
 | DC      |                       |           |
 | supply  |         capacitor + ------      ( o )  neon bulb
 |         |         10uF        ------      ( o )
 |         |                       |           |
 |        -|-----------------------+-----------|
 |---------|  

A simple relaxation oscillator may also be built from a 555 (wired as an inverting shmitt-trigger), and a single resistor/capacitor. Wiring is:

First, wire up an inverting schmitt-trigger from the 555.
 Pin 1 = Ground
 Pin 8 = Positive
 Pins 4,5,7 are left unconnected
 Pin 3 = Output.
 Pins 2,6 are connected together.
Then, connect the RC between pin 3 and ground, with pins 2,6 connected to the junction:
  PIN3 ----\/\/\/----PIN2,6----||-----GND

Note: The "normal" 555 astable configuration (using pins 2,6,7, and having 2 resistors and a capacitor) is not a relaxation oscillator: it is more complex.