Metronome circuit with a 555 timer
This Metronome circuit with adjustable BPM (beats per minute) using a 555 timer, allows those who study or are music fans, to keep the timing, quite accurately for a long period of time. Very important to keep the same rhythm of the music that is played.
How the Metronome circuit works?
The project is based on the well known 555 IC plus two transistors and some additional components.
It is important, in a suitable adjustment, to maintain the timing as constant as possible over a long period of time. So here are two Trimmers (VR1, VR3), a potentiometer and a transistor (Q1).
Transistor Q1 maintain the linearity of operation of the electronics Metronome. The 555 timer works in its astable configuration and the output is handled through the PNP Q2 transistor and a typical 8 ohms impedance miniature speaker.
The number of pulses per second (20 to 208) is obtained by varying the potentiometer VR2.
- Trimmer VR1 is adjusted to obtain the minimum number of pulses (40).
- Trimmer VR3 is adjusted to obtain the maximum number of pulses (288).
The entire assembly of the Metronome circuit is powered by a 12 volt battery or with a power supply with the same voltage. A portable metronome can be obtained if we include the 12 volts power source in the same circuit.
555 Timer Pinout
List of components for the Metronome circuit
- 1 555 IC Timer (IC1)
- 1 PNP NTE 234 transistor (Q1)
- 1 PNP NTE 2658 transistor (Q2)
- 1 10K resistor (R1)
- 1 330K resistor (R2)
- 1 100K resistor (R3)
- 2 1K resistors (R4,R5)
- 1 10K Trimmer (VR1)
- 1 50K Trimmer (VR3)
- 1 10K potentiometer (VR2)
- 1 100uF electrolytic capacitor (C1)
- 1 1uF capacitor (C2)
- 1 10nF capacitor (C3)
- 1 Switch (SW1)