This astable multivibrator with a dual triode valve operates in an audio frequency range determined by the capacitors. The circuit is from an old documentation about oscilloscopes and the power can be made with a source of about 50 mA.
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This astable multivibrator with a dual triode valve operates in an audio frequency range determined by the capacitors. The circuit is from an old documentation about oscilloscopes and the power can be made with a source of about 50 mA.