516 Relaxation oscillator
516 : Relaxation oscillator
- Author: Matt Venn
- Description: A relaxation oscillator
- GitHub repository
- Open in 3D viewer
- Clock: 0 Hz
- Feedback: ✅ 1 🟡 1
How it works
In electronics a relaxation oscillator is a nonlinear electronic oscillator circuit that produces a nonsinusoidal repetitive output signal, such as a triangle wave or square wave.
The R&C have been chosen to make a ~2MHz signal. An inverter after the oscillator makes a full swing square wave.
How to test
Measure the oscillator out on pin 0 (tbc, might cause issues due to the analog mux parasitics). Measure the square wave out on digital output pin 0.
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | inverted output of oscillator | ||
| 1 | |||
| 2 | |||
| 3 | |||
| 4 | |||
| 5 | |||
| 6 | |||
| 7 |
Analog pins
ua | PCB Pin | Internal index | Description |
|---|---|---|---|
| 0 | B4 | 10 | analog oscillator output |
User feedback
- smunaut: Works. Oscillates at around 1 MHz. The 10k pulldown needs to be cut/removed or it will load the output too much and it won't oscillate. Frequency is also very dependent on the loading on the ua pin. ( scope probe or finger will change freq by 10% easily )
- mattvenn👑: outputs at 1.1Mhz on my board. Important not to load the analog output or it will stop oscillating (there is no buffer)