Free Simple Circuit Diagram
The transistor is biased in class A. That’s mean the collector current flows all the time. This current can increase or decrease, caused by the input signal which increases and decreases the forward bias. This increasing or decreasing depends on the input signal, but never stop, even in the lowest level of input (the lower peak of the waveform). These […]
Read moreThe output of this circuit is push-pull and consumes less than 3mA (with no signal) but drives the earpiece to a very loud level when audio is detected. Because the whole circuit is Dc coupled, its extremely difficult to set up. Basically you don’t know where to start with the biasing. 8k2 between the emitter of the first transistor and […]
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Circuit below is a very sensitive 3-transistor amplifier using a speaker transformer. This can be wound on a short length of ferrite rod as show above or 150 turns on a 10mH choke. The biasing of the middle transistor is set for 3 V supply. During idle conditions and the quiescent current is just 5mA, the second and third transistors […]
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We can also operate TDA8932B/33(B) from a symmetrical supply. On this diagram, three half supply voltage buffers are disabled. When supplied from a symmetrical supply, HVPREF (Pin 11), HVP1 (pin 30) and HVP2 (Pin 19) should be connected to ground. Here’s the circuit diagram: Compared to an asymmetrical supply, a symmetrical supply has some benefits. First, the size of the […]
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