Output Relay Delay Audio Amplifier Circuit Diagram
This is a simple ambit which I congenital to one of my audio amplifier projects to ascendancy the apostle achievement relay. The purpose of this ambit is to ascendancy the broadcast which turns on the apostle achievement broadcast in the audio amplifier. The abstraction of the ambit is adjournment about 5 abnormal ofter the ability up until the spakers are switched to the amplfier achievement to abstain annoying “thump” complete from the speakers. Another feeature of this ambit is that is disconnects the apostle immdiatly back the ability in the amplifier is cut off, so avoinding sometimes awful sounds back you about-face the equipments off.
Output Broadcast Adjournment Audio Amplifier Ambit Component list
C1 100 uF 40V electrolytic
C2 100 uF 40V electrolytic
D1 1N4007
D2 1N4148
Q1 BC547
R1 33 kohm 0.25W
R2 2.2 kohm 0.25W
RELAY 24V DC relay, braid attrition >300 ohm
Circuit operation
Then ability is activated to the ability ascribe of the circuit, the complete appearance of AC voltage accuse C1. Then C2 starts to allegation boring through R1. Back the voltage in C2 rises, the emitter achievement voltage of Q1 rises tigether with voltage on C2. Back the achievement voltage of Q2 is aerial abundant (typically about 16..20V) the broadcast goes to on accompaniment and the broadcast witches affix the speakers to the amplifier output. It takes about about 5 abnormal afterwards ability up until the broadcast starts to condict (at complete time depends on the admeasurement of C2, broadcast voltage and ambit ascribe voltage).
When the ability is switched off, C1 will apart it’s energu absolutely quicly. Additionally C2 will be answerable absolutely quicly through R2. In beneath than 0.5 abnormal the speakers are broken from the amplifier output.
Notes on the circuit
This ambit is not the best authentic and affected design, but it has formed accurately in my baby homebuilt PA amplifier. This ambit can be additionally acclimated in abounding added applications area a about-face on adjournment of few abnormal is needed. The adjournment time can be added by application bigger C2 and decreased by application a abate C2 value. Note that the adjournment is not actual authentic because of artlessness of this ambit and ample altruism of archetypal electrolytic capacitors (can be -20%..+50% in some capcitors).