speaker as a microphone Archives - Amplifier Circuit Design https://amplifiercircuit.net/tag/speaker-as-a-microphone Amplifier Project Schematic Diagram Sat, 24 Dec 2011 04:51:03 +0000 en-US hourly 1 103688205 Preamp for Speakers as a Microphone 2 https://amplifiercircuit.net/preamp-for-the-speakers-as-a-microphone-2.html https://amplifiercircuit.net/preamp-for-the-speakers-as-a-microphone-2.html#respond Wed, 26 Oct 2011 02:24:04 +0000 http://amplifiercircuit.net/?p=702 The previous Preamp for the speakers as a microphone installation is indeed simple, but has virtually no gain. It is quite possible to add a second transistor to fill the gap, as […]

The post Preamp for Speakers as a Microphone 2 appeared first on Amplifier Circuit Design.

]]> Preamp for the speakers as a microphone 2The previous Preamp for the speakers as a microphone installation is indeed simple, but has virtually no gain. It is quite possible to add a second transistor to fill the gap, as shown in above diagram.

Note that the resistor R1 serves as the polarization of the two transistors Q1 and Q2. At the same time, the transistor input matching has become an NPN.

Parts list :

R1 : 470
R3 : 82K
R4 : 1K
R5 : 1K5
C1 : 47uF
C2 : 22uF
C3 : 100uF
C4 : 56pF
Q1, Q2 : BC109

The post Preamp for Speakers as a Microphone 2 appeared first on Amplifier Circuit Design.

]]> https://amplifiercircuit.net/preamp-for-the-speakers-as-a-microphone-2.html/feed 0 702 Preamp for Speaker as a Microphone https://amplifiercircuit.net/preamp-for-the-speakers-as-a-microphone.html https://amplifiercircuit.net/preamp-for-the-speakers-as-a-microphone.html#respond Tue, 25 Oct 2011 03:00:59 +0000 http://amplifiercircuit.net/?p=698 This Microphone Preamp circuit shows that it is possible to use the speaker as a microphone, and is specifically designed […]

The post Preamp for Speaker as a Microphone appeared first on Amplifier Circuit Design.

]]> Preamp for the speakers as a microphoneThis Microphone Preamp circuit shows that it is possible to use the speaker as a microphone, and is specifically designed to beginners because of its simplicity. Power consumption, of about 2mA, allowing the circuit is operated a few hours on a single 9V battery. However, it does not prevent you to use a stable power supply, or solar cells …

Sources : This setting is described by J. England Smith, the magazine ETI in January 1979. It is also found in an old French electronic magazine, the same scheme but with different component values​​.

Parts list :

R1 : 470/220K
R2 : 27K/22K
C1 : 33uF/4U7
C2 : 470nF/2u2
Q1 : 2N2907

The post Preamp for Speaker as a Microphone appeared first on Amplifier Circuit Design.

]]> https://amplifiercircuit.net/preamp-for-the-speakers-as-a-microphone.html/feed 0 698