This interesting transistor circuit has several effects and an included amplifier. The circuit is monophonic and powered by standard batteries. The number of keys can be changed.
This circuit is from a documentation from the 90s. The transistor can be any general-purpose FET...
Found in an Elektor from the 90's, this double door-bell drive circuit switches a relay by...
Using a CA3130, this circuit generates signals from approximately 550 kHz to 1.6 MHz using a...