Amplifier relay

Sometimes we need to activate a relay (relay), with a very weak signal, for example a source that provides about 5µA, this is the role we propose the following circuit.

With just a signal of 5 µA. can be turned over who should have a coil voltage power line, for example if we are going to use a source of 12 volt CD, this must be the voltage that supports the coil. The transistors Q1 and Q2 are in Darlington configuration, when a signal is present at the entrance through R1 serving as limiting, will result in Q1 and this in turn activates a Q2, motivating this by current flow through K1, This closing its contacts and thus activating the load on them. The mission of D1 is to avoid false contacts.

List of components
Semiconductors:
Q1, Q2: BC548
D1: 1N4004
Resistors 1/4 watt:
R1: 1.5 MΩ
R2: 10 kΩ
Others:
K1: relays (relay relay) to 12 volts.

pcb expensive components of the amp relay

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