Current drain is fairly high in this circuit so a suitable power supply is required. The duration the tone takes to rise and fall is determined by the 10u and 22k resistor. These values may be varied for different effects.
Transistor 2N3702 description
This device designed for use as PNP general purpose amplifier and switches requiring collector currents to 300mA.
Absolute Maximum Ratings
- Collector-Emitter Voltage (VCEO ): -25 V.
- Collector-Base Voltage (VCBO ): -40 V.
- Emitter-Base Voltage (VEBO ): -5.0 V.
- Collector Current - Continuous (IC): -500 mA.
- Operating and Storage Junction Temperature Range (TJ, TST): -55 ~ +150 C.
- Current Gain (hFE DC ): 60 - 300.
Pin transistor BC 108
- Low current (max. 100 mA).
- Low voltage (max. 45 V).
- Current Gain (hFE DC) : 110 - 450.