A key chain grounds the resistor chain and the world's most popular timer circuit 555 delivers the sound of a press directly to the speaker. Powered by a single 9V clip-on battery.
- Operating voltage: 9VDC
- max. power consumption max. 75mA (5mA at idle).
- Thirteen buttons
- by changing the resistance values of the chain, you can change the scale of the note as you like
- PCB dimensions: 106 x 32 mm
- Ø 57 mm miniature speaker (8ohm 0,25W) included
