This interesting circuit found in American documentation generates a busy signal, without you having to take the phone off the hook if you do not want to answer. The components used are common.
This transmitter was sent by contributing reader Adriano Muniz Moura from Pirapora – MG. It is in...
This circuit indicates whether the voltage to be measured is higher or lower than the zener diode...
An interesting application that can be implemented with the LM139 is the pulse width modulator. This is...