This circuit detects the presence of a constant magnetic field, such as that produced by a permanent magnet. This detection is done by approximating the field of coils L1 or L2. The indication is made through a 1 mA full scale analog instrument. The 5 to 8 V supply can be made from batteries. The circuit consists of a 15 kHz oscillator. The circuit is from a Popular Electronics from 1991. The transistors can be the BC548.
| Clique na imagem para ampliar |
